ETC TEA1751T

TEA1751T; TEA1751LT
GreenChip III SMPS control IC
Rev. 02 — 23 December 2009
Product data sheet
1. General description
The GreenChip III is the third generation of green Switched Mode Power Supply (SMPS)
controller ICs. The TEA1751(L)T (TEA1751T and TEA1751LT) combines a controller for
Power Factor Correction (PFC) and a flyback controller. Its high level of integration allows
the design of a cost-effective power supply with a very low number of external
components.
The special built-in green functions provide high efficiency at all power levels. This applies
to quasi-resonant operation at high power levels, quasi-resonant operation with valley
skipping, as well as to reduced frequency operation at lower power levels. At low power
levels, the PFC switches off to maintain high efficiency.
During low power conditions, the flyback controller switches to frequency reduction mode
and limits the peak current to 25 % of its maximum value. This will ensure high efficiency
at low power and good standby power performance while minimizing audible noise from
the transformer.
The TEA1751(L)T is a MultiChip Module, (MCM), containing two chips. The proprietary
high voltage BCD800 process which makes direct start-up possible from the rectified
universal mains voltage in an effective and green way. The second low voltage SIlicon On
Insulator (SIOI) is used for accurate, high speed protection functions and control.
The TEA1751(L)T enables highly efficient and reliable supplies with power requirements
up to 250 W, to be designed easily and with a minimum number of external components.
2. Features
2.1 Distinctive features
„
„
„
„
Integrated PFC and flyback controller.
Universal mains supply operation (70 V (AC) to 276 V (AC)).
Dual boost PFC with accurate maximum output voltage (NXP patented).
High level of integration, resulting in a very low external component count and a
cost-effective design.
2.2 Green features
„ On-chip start-up current source.
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
2.3 PFC green features
„ Valley/zero voltage switching for minimum switching losses (NXP patented).
„ Frequency limitation to reduce switching losses.
„ PFC is switched off when a low load is detected at the flyback output.
2.4 Flyback green features
„ Valley switching for minimum switching losses (NXP patented).
„ Frequency reduction with fixed minimum peak current at low power operation to
maintain high efficiency at low output power levels.
2.5 Protection features
„ Safe restart mode for system fault conditions.
„ Continuous mode protection by means of demagnetization detection for both
converters (NXP patented).
„ UnderVoltage Protection (UVP) (foldback during overload).
„ Accurate OverVoltage Protection (OVP) for both converters (adjustable for flyback
converter).
„ Mains voltage independent OverPower Protection (OPP)
„ Open control loop protection for both converters. The open loop protection on the
flyback converter is latched on the TEA1751L and safe restart on the TEA1751.
„ IC overtemperature protection.
„ Low and adjustable OverCurrent Protection (OCP) trip level for both converters.
„ General purpose input for latched protection, e.g. to be used for system
OverTemperature Protection (OTP).
3. Applications
„ The device can be used in all applications that require an efficient and cost-effective
power supply solution up to 250 W. Notebook adapters in particular can benefit from
the high level of integration.
4. Ordering information
Table 1.
Ordering information
Type number
Package
Name
Description
Version
TEA1751T
SO16
plastic small outline package; 16 leads; body width 3.9 mm
SOT109-1
TEA1751LT
SO16
plastic small outline package; 16 leads; body width 3.9 mm
SOT109-1
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
2 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
5. Block diagram
PFCDRIVER
PFC DRIVER
1.12 V
PFC GATE
3.5 V
FBDRIVER
12
13
DRV
FB DRIVER
80 μA
DRV
5 LATCH
FB GATE
EXT PROT
LOW
VIN
1.25 V
VINSENSE 7
PROT
BOOST
LATCH
RESET
PFCCOMP 6
MAX
R
PFC PROT
PROT
ENABLE PFC
R
Q
Q
S
LOW
POWER
PFC
OSC
3.7 V
2.50 V
15 μA
VCC GOOD
VoSTART FB
LOW POWER
EXT PROT
SMPS
CONTROL
TIMEOUT
EXT PROT
OTP
OvpFB
LATCH RESET
S (TEA1751L only)
S
LATCHED
S
PROTECTION
S
R
LOW VIN
VoOVP
PFC
PROT
VoSTART FB
VoSHORT
FB
OSC
TON MAX
2.7 V
BOOST
TIMEOUT
TON MAX
VoSHORT
VUVLO
PFC DRIVER
ENABLE PFC
60 μA
PFCAUX 8
TIME
OUT
3 FBCTRL
STARTFB
START STOP
PFC
OPP
MIN
OCP
FB
DRIVER
BLANK
10 FBSENSE
PROT
BLANK
500 mV
30 μA
Freq. Red.
OCP
PFCSENSE 11
3.5 V
LOW
POWER
1.25 V
VOSENSE 9
2.5 V
Freq
Red.
ENABLE
FB
S
SOFT START
VALLEY
DETECT
PROT
EXT PROT
Vstartup
Vth(UVLO)
START STOP PFC
S (TEA1751 only)
S
SAFE
S RESTART
R PROTECTION
CHARGE
OPP
VALLEY
DETECT
OPP
OVP
OvpFB
INTERNAL
SUPPLY
OTP
ZCS
START
SOFT
VCC GOOD
CHARGE
CONTROL
TIMER 4 μs
PFCGATE
60 μA
ENABLE FB
START FB
COUNTER
4 FBAUX
CHARGE
Vstartup
ZCS
TIMER 50 μs
Vth(UVLO)
FB GATE
TEMP
OTP
80 mV
100 mV
16
HV
1
VCC
2
GND
014aaa299
Remark:
For the TEA1751L the time-out is latched.
For the TEA1751 the time-out is safe restart.
Fig 1.
Block diagram
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
3 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
6. Pinning information
6.1 Pinning
VCC
1
16 HV
GND
2
15 HVS
FBCTRL
3
14 HVS
FBAUX
4
13 FBDRIVER
TEA1751(L)T
LATCH
5
12 PFCDRIVER
PFCCOMP
6
11 PFCSENSE
VINSENSE
7
10 FBSENSE
PFCAUX
8
9
VOSENSE
014aaa300
Fig 2.
Pin configuration: TEA1751(L)T (SOT109-1)
6.2 Pin description
Table 2.
Pin description
Symbol
Pin
Description
VCC
1
supply voltage
GND
2
ground
FBCTRL
3
control input for flyback
FBAUX
4
input from auxiliary winding for demagnetization timing and
overvoltage protection for flyback
LATCH
5
general purpose protection input
PFCCOMP
6
frequency compensation pin for PFC
VINSENSE
7
sense input for mains voltage
PFCAUX
8
input from auxiliary winding for demagnetization timing for PFC
VOSENSE
9
sense input for PFC output voltage
FBSENSE
10
programmable current sense input for flyback
PFCSENSE
11
programmable current sense input for PFC
PFCDRIVER
12
gate driver output for PFC
FBDRIVER
13
gate driver output for flyback
HVS
14, 15
high voltage safety spacer, not connected
HV
16
high voltage start-up and valley sensing of flyback part
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
4 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
7. Functional description
7.1 General control
The TEA1751(L)T contains a controller for a power factor correction circuit as well as a
controller for a flyback circuit. A typical configuration is shown in Figure 3.
12
8
6
11
9
16 13
10
TEA1751(L)T
7
3
2
4
1
014aaa301
Fig 3.
Typical configuration
7.1.1 Start-up and UnderVoltage LockOut (UVLO)
Initially the capacitor on the VCC pin is charged from the high voltage mains via the HV pin.
As long as VCC is below Vtrip, the charge current is low. This protects the IC if the VCC pin
is shorted to ground. For a short start-up time the charge current above Vtrip is increased
until VCC reaches Vth(UVLO). If VCC is between Vth(UVLO) and Vstartup, the charge current is
low again, ensuring a low duty cycle during fault conditions.
The control logic activates the internal circuitry and switches off the HV charge current
when the voltage on pin VCC passes the Vstartup level. First, the LATCH pin current source
is activated and the soft start capacitors on the PFCSENSE and FBSENSE pins are
charged. When the LATCH pin voltage exceeds the Ven(LATCH) voltage and the soft start
capacitor on the PFCSENSE pin is charged, the PFC circuit is activated. Also the flyback
converter is activated (providing the soft start capacitor on the FBSENSE pin is charged).
The output voltage of the flyback converter is then regulated to its nominal output voltage.
The IC supply is taken over by the auxiliary winding of the flyback converter. See Figure 4.
If during start-up the LATCH pin does not reach the Ven(LATCH) level before VCC reaches
Vth(UVLO), the LATCH pin output is deactivated and the charge current is switched on
again.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
5 of 29
NXP Semiconductors
TEA1751T; TEA1751LT
GreenChip III SMPS control IC
As soon as the flyback converter is started, the voltage on the FBCTRL pin is monitored. If
the output voltage of the flyback converter does not reach its intended regulation level in a
predefined time, the voltage on the FBCTRL pin reaches the Vto(FBCTRL) level and an error
is assumed. The TEA1751 then initiates a safe restart, while in the TEA1751L the
protection is latched.
When one of the protection functions is activated, both converters stop switching and the
VCC voltage drops to Vth(UVLO). A latched protection recharges the capacitor CVCC via the
HV pin, but does not restart the converters. For a safe restart protection, the capacitor is
recharged via the HV pin and the device restarts (see block diagram, Figure 1).
In the event of an overvoltage protection of the PFC circuit, VVOSENSE > Vovp(VOSENSE),
only the PFC controller stops switching until the VOSENSE pin voltage drops below
VOVP(VOSENSE) again. Also, if a mains undervoltage is detected
VVINSENSE < Vstop(VINSENSE), only the PFC controller stops switching until
VVINSENSE > Vstart(VINSENSE) again.
When the voltage on pin VCC drops below the undervoltage lockout level, both controllers
stop switching and reenter the safe restart mode. In the safe restart mode the driver
outputs are disabled and the VCC pin voltage is recharged via the HV pin.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
6 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
IHV
Vstartup
Vth(UVLO)
Vtrip
VCC
Vstart(VINSENSE)
VINSENSE
VEN(LATCH)
LATCH
PROTECTION
soft start
PFCSENSE
PFCDRIVER
soft start
FBSENSE
FBDRIVER
Vto(FBCTRL)
FBCTRL
Vstart(fb)
VOSENSE
VO
charging VCC
capacitor
Fig 4.
starting
converters
normal
operation
protection
restart
014aaa156
Start-up sequence, normal operation and restart sequence
7.1.2 Supply management
All internal reference voltages are derived from a temperature compensated and trimmed
on-chip band gap circuit. Internal reference currents are derived from a temperature
compensated and trimmed on-chip current reference circuit.
7.1.3 Latch input
Pin LATCH is a general purpose input pin, which can be used to switch off both
converters. The pin sources a current IO(LATCH) (80 μA typical). Switching off both
converters is stopped as soon as the voltage on this pin drops below 1.25 V.
At initial start-up the switching is inhibited until the capacitor on the LATCH pin is charged
above 1.35 V (typical). No internal filtering is done on this pin. An internal zener clamp of
2.9 V (typical) protects this pin from excessive voltages.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
7 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
7.1.4 Fast latch reset
In a typical application the mains can be interrupted briefly to reset the latched protection.
The PFC bus capacitor, Cbus, does not have to discharge for this latched protection to
reset.
Typically the PFC bus capacitor, Cbus, has to discharge for the VCC to drop to this reset
level. When the latched protection is set, the clamping circuit of the VINSENSE circuit is
disabled. (see also Section 7.2.9) As soon as the VINSENSE voltage drops below
750 mV (typical) and after that is raised to 870 mV (typical), the latched protection is reset.
The latched protection is also reset by removing both the voltage on pin VCC and on
pin HV.
7.1.5 Overtemperature protection
An accurate internal temperature protection is provided in the circuit. When the junction
temperature exceeds the thermal shutdown temperature, the IC stops switching. As long
as OTP is active, the capacitor CVCC is not recharged from the HV mains. The OTP circuit
is supplied from the HV pin if the VCC supply voltage is not sufficient.
OTP is a latched protection. It can be reset by removing both the voltage on pin VCC and
on pin HV or by the fast latch reset function. (See Section 7.1.4)
7.2 Power factor correction circuit
The power factor correction circuit operates in quasi-resonant or discontinuous
conduction mode with valley switching. The next primary stroke is only started when the
previous secondary stroke has ended and the voltage across the PFC MOSFET has
reached a minimum value. The voltage on the PFCAUX pin is used to detect transformer
demagnetization and the minimum voltage across the external PFC MOSFET switch.
7.2.1 ton control
The power factor correction circuit is operated in ton control. The resulting mains harmonic
reduction of a typical application is well within the class-D requirements.
7.2.2 Valley switching and demagnetization (PFCAUX pin)
The PFC MOSFET is switched on after the transformer is demagnetized. Internal circuitry
connected to the PFCAUX pin detects the end of the secondary stroke. It also detects the
voltage across the PFC MOSFET. The next stroke is started when the voltage across the
PFC MOSFET is at its minimum in order to reduce switching losses and ElectroMagnetic
Interference (EMI) (valley switching).
If no demagnetization signal is detected on the PFCAUX pin, the controller generates a
zero current signal (ZCS), 50 μs (typical) after the last PFCGATE signal.
If no valley signal is detected on the PFCAUX pin, the controller generates a valley signal
4 μs (typical) after demagnetization was detected.
To protect the internal circuitry during lightning events, for example, it is advisable to add a
5 kΩ series resistor to this pin. To prevent incorrect switching due to external disturbance,
the resistor should be placed close to the IC on the printed-circuit board.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
8 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
7.2.3 Frequency limitation
To optimize the transformer and minimize switching losses, the switching frequency is
limited to fsw(PFC)max. If the frequency for quasi-resonant operation is above the fsw(PFC)max
limit, the system switches over to discontinuous conduction mode. Also here, the PFC
MOSFET is only switched on at a minimum voltage across the switch (valley switching).
7.2.4 Mains voltage compensation (VINSENSE pin)
The mathematical equation for the transfer function of a power factor corrector contains
the square of the mains input voltage. In a typical application this results in a low
bandwidth for low mains input voltages, while at high mains input voltages the Mains
Harmonic Reduction (MHR) requirements may be hard to meet.
To compensate for the mains input voltage influence, the TEA1751(L)T contains a
correction circuit. Via the VINSENSE pin the average input voltage is measured and the
information is fed to an internal compensation circuit. With this compensation it is possible
to keep the regulation loop bandwidth constant over the full mains input range, yielding a
fast transient response on load steps, while still complying with class-D MHR
requirements.
In a typical application, the bandwidth of the regulation loop is set by a resistor and two
capacitors on the PFCCOMP pin.
7.2.5 Soft start-up (pin PFCSENSE)
To prevent audible transformer noise at start-up or during hiccup, the transformer peak
current, IDM, is increased slowly by the soft start function. This can be achieved by
inserting RSS1 and CSS1 between pin PFCSENSE and current sense resistor RSENSE1.
An internal current source charges the capacitor to VPFCSENSE = Istart(soft)PFC × RSS1. The
voltage is limited to Vstart(soft)PFC.
The start level and the time constant of the increasing primary current level can be
adjusted externally by changing the values of RSS1 and CSS1.
τsoftstart = 3 × R SS1 × C SS1
The charging current Istart(soft)PFC flows as long as the voltage on pin PFCSENSE is
below 0.5 V (typ). If the voltage on pin PFCSENSE exceeds 0.5 V, the soft start current
source starts limiting current Istart(soft)PFC. As soon as the PFC starts switching, the
Istart(soft)PFC current source is switched off; see Figure 5.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
9 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
Istartup(soft)PFC ≤ 60 μA
S1
SOFT START
CONTROL
RSS1
11
PFCSENSE
CSS1
RSENSE1
OCP
0.5 V
014aaa157
Fig 5.
Soft start-up of PFC
7.2.6 Low power mode
When the output power of the flyback converter (see Section 7.3) is low, the flyback
converter switches over to frequency reduction mode. When frequency reduction mode is
entered by the flyback controller, the power factor correction circuit is switched off to
maintain high efficiency.
During low power mode operation the PFCCOMP pin is clamped to a minimal voltage of
2.7 V (typical) and a maximum voltage of 3.9 V (typical). The lower clamp voltage limits
the maximum power that is delivered when the PFC is switched on again. The upper
clamp voltage ensures that the PFC can return to its normal regulation point in a limited
amount of time when returning from low power mode.
As soon as the flyback converter leaves the frequency reduction mode, the power factor
correction circuit restores normal operation. To prevent continuous switching on and off of
the PFC circuit, a small hysteresis is build in, (60 mV (typical) on the FBCTRL pin).
7.2.7 Dual boost PFC
The PFC output voltage is modulated by the mains input voltage. The mains input voltage
is measured via the VINSENSE pin. The current is sourced from the VOSENSE pin if the
voltage on the VINSENSE pin drops below 2.2 V (typical). To ensure the stability of the
switch-over 200 mV is inserted around the 2.2 V, see Figure 6.
For low VINSENSE input voltages, the output current is 15 μA (typical). This output
current, in combination with the resistors on the VOSENSE pin, sets the lower PFC output
voltage level at low mains voltages. At high mains input voltages the current is switched to
zero. The PFC output voltage will then be at its maximum. As this current is zero in this
situation, it does not effect the accuracy of the PFC output voltage.
For proper switch-off behavior, the VOSENSE current is switched to its maximum value,
(15 μA (typical)), as soon as the voltage on pin VOSENSE drops below 2.1 V (typical).
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
10 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
2.2 V
VVINSENSE
−15 μA
II(VOSENSE)
014aaa097
Fig 6.
Voltage to current transfer function for dual boost PFC
7.2.8 Overcurrent protection (PFCSENSE pin)
The maximum peak current is limited cycle-by-cycle by sensing the voltage across an
external sense resistor, RSENSE1, on the source of the external MOSFET. The voltage is
measured via the PFCSENSE pin.
7.2.9 Mains undervoltage lockout / brownout protection (VINSENSE pin)
To prevent the PFC from operating at very low mains input voltages, the voltage on the
VINSENSE pin is sensed continuously. As soon as the voltage on this pin drops below the
Vstop(VINSENSE) level, switching of the PFC is stopped.
The voltage on pin VINSENSE is clamped to a minimum value,
Vstart(VINSENSE) + ΔVpu(VINSENSE), for a fast restart as soon as the mains input voltage is
restored after a mains dropout.
7.2.10 Overvoltage protection (VOSENSE pin)
To prevent output overvoltage during load steps and mains transients, an overvoltage
protection circuit is built in.
As soon as the voltage on the VOSENSE pin exceeds the Vovp(VOSENSE) level, switching
of the power factor correction circuit is inhibited. Switching of the PFC recommences as
soon as the VOSENSE pin voltage drops below the Vovp(VOSENSE) level again.
When the resistor between pin VOSENSE and ground is open, the overvoltage protection
is also triggered.
7.2.11 PFC open loop protection (VOSENSE pin)
The power factor correction circuit does not start switching until the voltage on the
VOSENSE pin is above the Vth(ol)(VOSENSE) level. This protects the circuit from open loop
and VOSENSE short situations.
7.2.12 Driver (pin PFCDRIVER)
The driver circuit to the gate of the power MOSFET has a current sourcing capability of
typically −500 mA and a current sink capability of typically 1.2 A. This permits fast turn-on
and turn-off of the power MOSFET for efficient operation.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
11 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
7.3 Flyback controller
The TEA1751(L)T includes a controller for a flyback converter. The flyback converter
operates in quasi-resonant or discontinuous conduction mode with valley switching. The
auxiliary winding of the flyback transformer provides demagnetization detection and
powers the IC after start-up.
7.3.1 Multimode operation
The TEA1751(L)T flyback controller can operate in several modes; see Figure 7.
fsw(fb)max
PFC off
PFC on
frequency
reduction
switching frequency
discontinuous
with valley
switching
quasi resonant
output power
014aaa158
Fig 7.
Multimode operation flyback
At high output power the converter switches to quasi-resonant mode. The next converter
stroke is started after demagnetization of the transformer current. In quasi-resonant mode
switching losses are minimized as the converter only switches on when the voltage across
the external MOSFET is at its minimum (valley switching, see also Section 7.3.2).
To prevent high frequency operation at lower loads, the quasi-resonant operation changes
to discontinuous mode operation with valley skipping in which the switching frequency is
limited for EMI to fsw(fb)max (125 kHz typical). Again, the external MOSFET is only switched
on when the voltage across the MOSFET is at its minimum.
At very low power and standby levels the frequency is controlled down by a Voltage
Controlled Oscillator (VCO). The minimum frequency can be reduced to zero. During
frequency reduction mode, the primary peak current is kept at a minimal level of Ipkmax/4
to maintain a high efficiency. (Ipkmax is the maximum primary peak current set by the
sense resistor and the maximum sense voltage.) As the primary peak current is low in
frequency reduction operation (Ipk = Ipkmax/4), no audible noise is noticeable at
switching frequencies in the audible range. Valley switching is also active in this mode.
In frequency reduction mode the PFC controller is switched off and the flyback maximum
frequency changes linearly with the control voltage on the FBCTRL pin (see Figure 8 ).
For stable on and off switching of the PFC, the FBCTRL pin has a 50 mV (typical)
hysteresis. At no load operation the switching frequency can be reduced to (almost) zero.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
12 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
PFC off
fsw(fb)max
PFC on
frequency
reduction
switching frequency
discontinuous
with valley
switching
1.5 V
Fig 8.
VFBCTRL
quasi resonant
014aaa159
Frequency control of flyback part
7.3.2 Valley switching (HV pin)
Refer to Figure 9. A new cycle starts when the external MOSFET is activated. After the
on-time (determined by the FBSENSE voltage and the FBCTRL voltage), the MOSFET is
switched off and the secondary stroke starts. After the secondary stroke, the drain voltage
1
shows an oscillation with a frequency of approximately --------------------------------------------------- where Lp is
( 2 × π × ( Lp × Cd ) )
the primary self-inductance of the flyback transformer and Cd is the capacitance on the
drain node.
As soon as the internal oscillator voltage is high again and the secondary stroke has
ended, the circuit waits for the lowest drain voltage before starting a new primary stroke.
Figure 9 shows the drain voltage, valley signal, secondary stroke signal and the internal
oscillator signal.
Valley switching allows high frequency operation as capacitive switching losses are
reduced, see Equation 1. High frequency operation makes small and cost-effective
magnetics possible.
⎛ P = 1--- × C × V 2 × f⎞
d
⎝
⎠
2
(1)
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
13 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
primary
stroke
secondary
stroke
secondary
ringing
drain
valley
secondary
stroke
(2)
(1)
oscillator
014aaa027
(1) Start of new cycle at lowest drain voltage.
(2) Start of new cycle in a classical Pulse Width Modulation (PWM) system without valley detection.
Fig 9.
Signals for valley switching
7.3.3 Current mode control (FBSENSE pin)
Current mode control is used for the flyback converter for its good line regulation.
The primary current is sensed by the FBSENSE pin across an external resistor and
compared with an internal control voltage.The internal control voltage is proportional to
the FBCTRL pin voltage, see Figure 10.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
14 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
Vsense(fb)max
(V)
0.52 V
PFC off
PFC on
flyback
frequency
reduction
flyback
discontinuous
or QR
FBSENSE peak voltage
flyback
cycle skip
mode
0.13 V
1.4 V 1.5 V
2.0 V VFBCTRL (V)
014aaa160
Fig 10. Peak current control of flyback part
The driver output is latched in the logic, preventing multiple switch-on.
7.3.4 Demagnetization (FBAUX pin)
The system is always in quasi-resonant or discontinuous conduction mode. The internal
oscillator does not start a new primary stroke until the previous secondary stroke has
ended.
Demagnetization features a cycle-by-cycle output short circuit protection by immediately
lowering the frequency (longer off-time), thereby reducing the power level.
Demagnetization recognition is suppressed during the first tsup(xfmr_ring) time (2 μs typical).
This suppression may be necessary at low output voltages and at start-up and in
applications where the transformer has a large leakage inductance.
If pin FBAUX is open circuit or not connected, a fault condition is assumed and the
converter stops operating immediately. Operation restarts as soon as the fault condition is
removed.
7.3.5 Flyback control / time-out (FBCTRL pin)
The pin FBCTRL is connected to an internal voltage source of 3.5 V via an internal
resistor (typical resistance is 3 kΩ). As soon as the voltage on this pin is above
2.5 V (typical), this connection is disabled. Above 2.5 V the pin is biased with a small
current. When the voltage on this pin rises above 4.5 V (typical), a fault is assumed and
switching is inhibited. In the TEA1751 a restart will then be made, while in the TEA1751L
the protection will be latched.
When a small capacitor is connected to this pin, a time-out function can be created to
protect against an open control loop situation. (see Figure 11 and Figure 12) The time-out
function can be disabled by connecting a resistor (100 kΩ) to ground on the FBCTRL pin.
If the pin is shorted to ground, switching of the flyback controller is inhibited.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
15 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
In normal operating conditions, when the converter is regulating the output voltage, the
voltage on the FBCTRL pin is between 1.4 V and 2.0 V (typical values) from minimum to
maximum output power.
2.5 V
3.5 V
30 μA
4.5 V
3 kΩ
FBCTRL
TIME-OUT
014aaa049
Fig 11. Time-out protection circuit
4.5 V
2.5 V
VFBCTRL
output
voltage
intended output
voltage not
reached within
time-out time.
restart
intended output voltage
reached within time-out
time.
014aaa050
Fig 12. Time-out protection (signals), safe restart in the TEA1751
4.5 V
2.5 V
VFBCTRL
output
voltage
intended output
voltage not
reached within
time−out time.
latched
014aaa298
Fig 13. Time-out protection (signals), latched in the TEA1751L
TEA1751T_LT_2
Product data sheet
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Rev. 02 — 23 December 2009
16 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
7.3.6 Soft start-up (pin FBSENSE)
To prevent audible transformer noise during start-up, the transformer peak current, IDM is
slowly increased by the soft start function. This can be achieved by inserting a resistor and
a capacitor between pin 10, FBSENSE, and the current sense resistor.
An internal current source charges the capacitor to V = Istart(soft)fb × RSS2, with a maximum
of approximately 0.5 V.
The start level and the time constant of the increasing primary current level can be
adjusted externally by changing the values of RSS2 and CSS2.
τsoftstart = 3 × R SS2 × C SS2
The soft start current Istart(soft)fb is switched on as soon as VCC reaches Vstartup. When the
voltage on pin FBSENSE has reached 0.5 V, the flyback converter starts switching.
The charging current Istart(soft)(PFC) flows as long as the voltage on pin FBSENSE is below
approximately 0.5 V. If the voltage on pin FBSENSE exceeds 0.5 V, the soft start current
source starts limiting the current. After the flyback converter has started, the soft start
current source is switched off.
S2
Istart(soft)fb ≤ 60 μA
SOFT START
CONTROL
RSS2
10
FBSENSE
CSS2
RSENSE2
OCP
+
0.5 V
014aaa020
Fig 14. Soft start-up of flyback.
7.3.7 Maximum on-time
The flyback controller limits the ‘on-time’ of the external MOSFET to 40 μs (typical). When
the ‘on-time’ is longer than 40 μs, the IC stops switching and enters the safe restart mode.
7.3.8 Overvoltage protection (FBAUX pin)
An output overvoltage protection is implemented in the GreenChip III series. This works
for the TEA1751(L)T by sensing the auxiliary voltage via the current flowing into
pin FBAUX during the secondary stroke. The auxiliary winding voltage is a well-defined
replica of the output voltage. Voltage spikes are averaged by an internal filter.
If the output voltage exceeds the OVP trip level, an internal counter starts counting
subsequent OVP events. The counter has been added to prevent incorrect OVP detection
which might occur during ESD or lightning events. If the output voltage exceeds the OVP
trip level a few times and not again in a subsequent cycle, the internal counter counts
down at twice the speed it uses when counting up. However, when typically eight cycles of
TEA1751T_LT_2
Product data sheet
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Rev. 02 — 23 December 2009
17 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
subsequent OVP events are detected, the IC assumes a true OVP and the OVP circuit
switches the power MOSFET off. As the protection is latched, the converter only restarts
after the internal latch is reset. In a typical application the mains should be interrupted to
reset the internal latch.
The output voltage Vo(OVP) at which the OVP function trips, can be set by the
demagnetization resistor, RFBAUX :
Ns
(I
× R FBaux + V clamp ( FBAUX ) )
V o ( OVP ) = ----------N aux ovp ( FBaux )
where Ns is the number of secondary turns and Naux is the number of auxiliary turns of the
transformer. Current Iovp(FBAUX) is internally trimmed.
The value of RFBAUX can be adjusted to the turns ratio of the transformer, thus making an
accurate OVP detection possible.
7.3.9 Overcurrent protection (FBSENSE pin)
The primary peak current in the transformer is measured accurately cycle-by-cycle using
the external sense resistor Rsense2. The OCP circuit limits the voltage on pin FBSENSE to
an internal level (see also Section 7.3.3). The OCP detection is suppressed during the
leading edge blanking period, tleb, to prevent false triggering caused by switch-on spikes.
LEB (tleb)
OCP LEVEL
VFBSENSE
t
014aaa022
Fig 15. OCP leading edge blanking
7.3.10 Overpower protection
During the primary stroke of the flyback converter the input voltage of the flyback
converter is measured by sensing the current that is drawn from the pin FBAUX.
The current information is used to adjust the peak drain current of the flyback converter,
which is measured via pin FBSENSE. The internal compensation is such that an almost
input voltage independent maximum output power can be realized.
The OPP curve is given in Figure 16.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
18 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
014aaa096
0.6
VFBSENSE
(V)
0.52
0.5
0.4
0.37
0.3
−400
−360
−300
−200
−100
0
IFBAUX (μA)
Fig 16. Overpower protection curve
7.3.11 Driver (pin FBDRIVER)
The driver circuit to the gate of the external power MOSFET has a current sourcing
capability of typically −500 mA and a current sink capability of typically 1.2 A. This permits
fast turn-on and turn-off of the power MOSFET for efficient operation.
8. Limiting values
Table 3.
Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
Parameter
Conditions
Min
Max
Unit
−0.4
+38
V
−0.4
+5
V
Voltages
VCC
supply voltage
VLATCH
voltage on pin LATCH
VFBCTRL
voltage on pin FBCTRL
−0.4
+5
V
VPFCCOMP
voltage on pin PFCCOMP
−0.4
+5
V
VVINSENSE
voltage on pin VINSENSE
−0.4
+5
V
VVOSENSE
voltage on pin VOSENSE
−0.4
+5
V
VPFCAUX
voltage on pin PFCAUX
VFBSENSE
voltage on pin FBSENSE
current limited
−25
+25
V
current limited
−0.4
+5
V
current limited
−0.4
+5
V
voltage on pin HV
−0.4
+650
V
IFBCTRL
current on pin FBCTRL
−3
0
mA
IFBAUX
current on pin FBAUX
−1
+1
mA
IPFCSENSE
current on pin PFCSENSE
−1
+10
mA
IFBSENSE
current on pin FBSENSE
−1
+10
mA
IFBDRIVER
current on pin FBDRIVER
−0.8
+2
A
VPFCSENSE voltage on pin PFCSENSE
VHV
Currents
duty cycle < 10 %
TEA1751T_LT_2
Product data sheet
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Rev. 02 — 23 December 2009
19 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
Table 3.
Limiting values …continued
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
Parameter
IPFCDRIVER current on pin PFCDRIVER
Conditions
Min
Max
Unit
duty cycle < 10 %
−0.8
+2
A
-
5
mA
-
0.6
W
current on pin HV
IHV
General
Tamb < 75 °C
Ptot
total power dissipation
Tstg
storage temperature
−55
+150
°C
Tj
junction temperature
−40
+150
°C
ESD
electrostatic discharge
voltage
VESD
class 1
human body
model
pins 1 to 13
[1]
-
2000
V
pin 16 (HV)
[1]
-
1500
V
machine model
[2]
-
200
V
-
500
V
charged device
model
[1]
Equivalent to discharging a 100 pF capacitor through a 1.5 kΩ series resistor.
[2]
Equivalent to discharging a 200 pF capacitor through a 0.75 μH coil and a 10 Ω resistor.
9. Thermal characteristics
Table 4.
Thermal characteristics
Symbol
Parameter
Conditions
Typ
Unit
Rth(j-a)
thermal resistance from
junction to ambient
in free air; JEDEC test
board
124
K/W
10. Characteristics
Table 5.
Characteristics
Tamb = 25 °C; VCC = 20 V; all voltages are measured with respect to ground (pin 2); currents are positive when flowing into
the IC; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
VCC < Vtrip;
Vth(UVLO) < VCC < Vstartup
-
1.0
-
mA
Vtrip < VCC < Vth(UVLO)
-
5.4
-
mA
with auxiliary supply
8
20
40
μA
650
-
-
V
Start-up current source (pin HV)
IHV
VBR
current on pin HV
VHV > 80 V
breakdown voltage
Supply voltage management (pin VCC)
Vtrip
trip voltage
0.55
0.65
0.75
V
Vstartup
start-up voltage
21
22
23
V
TEA1751T_LT_2
Product data sheet
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Rev. 02 — 23 December 2009
20 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
Table 5.
Characteristics …continued
Tamb = 25 °C; VCC = 20 V; all voltages are measured with respect to ground (pin 2); currents are positive when flowing into
the IC; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
Vth(UVLO)
undervoltage lockout threshold
voltage
14
15
16
V
Vstart(hys)
hysteresis of start voltage
during start-up phase
-
300
-
mV
Vhys
hysteresis voltage
Vstartup − Vth(UVLO)
6.3
7
7.7
V
Ich(low)
low charging current
VHV > 80 V; VCC < Vtrip or
Vth(UVLO) < VCC < Vstartup
−1.2
−1.0
−0.8
mA
Ich(high)
high charging current
VHV > 80 V; Vtrip < VCC < Vth(UVLO)
−4.6
−5.4
−6.3
mA
ICC(oper)
operating supply current
no load on pin FBDRIVER and
PFCDRIVER
2.25
3
3.75
mA
Input voltage sensing PFC (pin VINSENSE)
Vstop(VINSENSE)
stop voltage on pin VINSENSE
0.86
0.89
0.92
V
Vstart(VINSENSE)
start voltage on pin VINSENSE
1.11
1.15
1.19
V
ΔVpu(VINSENSE)
pull-up voltage difference on
pin VINSENSE
active after Vstop(VINSENSE) is
detected
-
−100
-
mV
Ipu(VINSENSE)
pull-up current on pin
VINSENSE
active after Vstop(VINSENSE) is
detected
−55
−47
−40
μA
4.0
-
-
V
-
0.75
-
V
Vmvc(VINSENSE)max maximum mains voltage
compensation voltage on pin
VINSENSE
Vflr
fast latch reset voltage
Vflr(hys)
hysteresis of fast latch reset
voltage
-
0.12
-
V
II(VINSENSE)
input current on pin VINSENSE VVINSENSE > Vstop(VINSENSE) after
Vstart(VINSENSE) is detected
5
33
100
nA
Vbst(dual)
dual boost voltage
active after Vth(UVLO) is detected
current switch-over point
-
2.2
-
V
switch-over region
-
200
-
mV
VVOSENSE to IO(PFCCOMP)
60
80
100
μA/V
Loop compensation PFC (pin PFCCOMP)
gm
transconductance
IO(PFCCOMP)
output current on pin
PFCCOMP
Vclamp(PFCCOMP)
clamp voltage on pin
PFCCOMP
VVOSENSE = 3.3 V
33
39
45
μA
VVOSENSE = 2.0 V
−45
−39
−33
μA
2.9
V
Low power mode; PFC off; lower
clamp voltage
[1]
2.5
2.7
Upper clamp voltage
[1]
-
3.9
-
V
Vton(PFCCOMP)zero
zero on-time voltage on pin
PFCCOMP
3.4
3.5
3.6
V
Vton(PFCCOMP)max
maximum on-time voltage on
pin PFCCOMP
1.20
1.25
1.30
V
VVINSENSE = 3.3 V;
VPFCCOMP = Vton(PFCCOMP)max
3.6
4.5
5.0
μs
VVINSENSE = 0.9 V;
VPFCCOMP = Vton(PFCCOMP)max
30
40
53
μs
Pulse width modulator PFC
ton(PFC)
PFC on-time
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
21 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
Table 5.
Characteristics …continued
Tamb = 25 °C; VCC = 20 V; all voltages are measured with respect to ground (pin 2); currents are positive when flowing into
the IC; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
-
1.15
-
V
Output voltage sensing PFC (pin VOSENSE)
Vth(ol)(VOSENSE)
open-loop threshold voltage on
pin VOSENSE
Vreg(VOSENSE)
regulation voltage on pin
VOSENSE
Vovp(VOSENSE)
overvoltage protection voltage
on pin VOSENSE
Ibst(dual)
dual boost current
for IO(PFCCOMP) = 0
2.475 2.500 2.525 V
2.60
2.63
2.67
V
VVINSENSE < Vbst(dual) or
VVOSENSE < 2.1 V
-
-15
-
μA
VVINSENSE > Vbst(dual)
-
-30
-
nA
ΔV/Δt = 50 mV/μs
0.49
0.52
0.55
V
ΔV/Δt = 200 mV/μs
Overcurrent protection PFC (pin PFCSENSE)
Vsense(PFC)max
maximum PFC sense voltage
0.52
0.55
0.57
V
tleb(PFC)
PFC leading edge blanking
time
250
310
370
ns
Iprot(PFCSENSE)
protection current on pin
PFCSENSE
−50
-
−5
nA
−75
−60
−45
μA
0.46
0.50
0.54
V
Soft start PFC (pin PFCSENSE)
Istart(soft)PFC
PFC soft start current
Vstart(soft)PFC
PFC soft start voltage
Rstart(soft)PFC
PFC soft start resistance
12
-
-
kΩ
fsw(PFC)max
maximum PFC switching
frequency
100
125
150
kHz
toff(PFC)min
minimum PFC off-time
1.1
1.4
1.7
μs
-
-
1.7
V/μs
enabling voltage
Oscillator PFC
Valley switching PFC (pin PFCAUX)
(ΔV/Δt)vrec(PFC)
PFC valley recognition voltage
change with time
tvrec(PFC)
PFC valley recognition time
tto(vrec)PFC
VPFCAUX = 1 V peak-to-peak
[2]
-
-
300
ns
demagnetization to ΔV/Δt = 0
[3]
-
-
50
ns
3
4
6
μs
PFC valley recognition time-out
time
Demagnetization management PFC (pin PFCAUX)
Vth(comp)PFCAUX
comparator threshold voltage
on pin PFCAUX
−150
−100
−50
mV
tto(demag)PFC
PFC demagnetization time-out
time
40
50
60
μs
Iprot(PFCAUX)
protection current on pin
PFCAUX
VPFCAUX = 50 mV
−75
-
−5
nA
VPFCDRIVER = 2 V
-
−0.5
-
A
Driver (pin PFCDRIVER)
Isrc(PFCDRIVER)
source current on pin
PFCDRIVER
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
22 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
Table 5.
Characteristics …continued
Tamb = 25 °C; VCC = 20 V; all voltages are measured with respect to ground (pin 2); currents are positive when flowing into
the IC; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
Isink(PFCDRIVER)
sink current on pin
PFCDRIVER
VPFCDRIVER = 2 V
-
0.7
-
A
VPFCDRIVER = 10 V
-
1.2
-
A
-
11
12
V
μA
VO(PFCDRIVER)max
maximum output voltage on pin
PFCDRIVER
Overvoltage protection flyback (pin FBAUX)
Iovp(FBAUX)
overvoltage protection current
on pin FBAUX
279
300
321
Ncy(ovp)
number of overvoltage
protection cycles
6
8
12
60
80
110
mV
Demagnetization management flyback (pin FBAUX)
Vth(comp)FBAUX
comparator threshold voltage
on pin FBAUX
Iprot(FBAUX)
protection current on pin
FBAUX
VFBAUX = 50 mV
−50
-
−5
nA
Vclamp(FBAUX)
clamp voltage on pin FBAUX
IFBAUX = −500 μA
−1.0
−0.8
−0.6
V
IFBAUX = 500 μA
0.5
0.7
0.9
V
1.5
2
2.5
μs
tsup(xfmr_ring)
transformer ringing
suppression time
Pulse width modulator flyback
ton(fb)min
minimum flyback on-time
-
tleb
-
ns
ton(fb)max
maximum flyback on-time
32
40
48
μs
fsw(fb)max
maximum flyback switching
frequency
100
125
150
kHz
Vstart(VCO)FBCTRL
VCO start voltage on pin
FBCTRL
1.3
1.5
1.7
V
Vhys(FBCTRL)
hysteresis voltage on pin
FBCTRL
-
60
-
mV
ΔVVCO(FBCTRL)
VCO voltage difference on pin
FBCTRL
-
-0.1
-
V
Oscillator flyback
[4]
Peak current control flyback (pin FBCTRL)
VFBCTRL
voltage on pin FBCTRL
for maximum flyback peak current
1.85
2.0
2.15
V
Vto(FBCTRL)
time-out voltage on pin
FBCTRL
enable voltage
-
2.5
-
V
trip voltage
4.2
4.5
4.8
V
-
3
-
kΩ
VFBCTRL = 0 V
−1.4
−1.19 −0.93 mA
VFBCTRL = 2 V
−0.6
−0.5
−0.4
mA
VFBCTRL = 2.6 V
−36
−30
−24
μA
VFBCTRL = 4.1 V
−34.5 −28.5 −22.5 μA
Rint(FBCTRL)
internal resistance on pin
FBCTRL
IO(FBCTRL)
output current on pin FBCTRL
Ito(FBCTRL)
time-out current on pin
FBCTRL
Valley switching flyback (pin HV)
(ΔV/Δt)vrec(fb)
−75
flyback valley recognition
voltage change with time
TEA1751T_LT_2
Product data sheet
-
+75
V/μs
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
23 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
Table 5.
Characteristics …continued
Tamb = 25 °C; VCC = 20 V; all voltages are measured with respect to ground (pin 2); currents are positive when flowing into
the IC; unless otherwise specified.
Symbol
td(vrec-swon)
Parameter
Conditions
[5]
valley recognition to switch-on
delay time
Min
Typ
Max
Unit
-
150
-
ns
−75
−60
−45
μA
Soft start flyback (pin FBSENSE)
Istart(soft)fb
flyback soft start current
Vstart(soft)fb
flyback soft start voltage
Rstart(soft)fb
flyback soft start resistance
enable voltage
0.43
0.49
0.54
V
12
-
-
kΩ
ΔV/Δt = 50 mV/μs
0.49
0.52
0.55
V
ΔV/Δt = 200 mV/μs
Overcurrent protection flyback (pin FBSENSE)
Vsense(fb)max
maximum flyback sense
voltage
0.52
0.55
0.58
V
tleb(fb)
flyback leading edge blanking
time
255
305
355
ns
Istart(OPP)FBAUX
OPP start current on pin
FBAUX
-
−100
-
μA
Iopp(red)(FBAUX)
reduced overpower protection
current on pin FBAUX
Vsense(fb)max has reduced to
0.37 V
-
−360
-
μA
Driver (pin FBDRIVER)
Isrc(FBDRIVER)
source current on pin
FBDRIVER
VFBDRIVER = 2 V
-
−0.5
-
A
Isink(FBDRIVER)
sink current on pin FBDRIVER
VFBDRIVER = 2 V
-
0.7
-
A
VFBDRIVER = 10 V
-
1.2
-
A
-
11
12
V
1.23
1.25
1.27
V
VO(FBDRIVER)(max)
maximum output voltage on pin
FBDRIVER
LATCH input (pin LATCH)
Vprot(LATCH)
protection voltage on pin
LATCH
IO(LATCH)
output current on pin LATCH
Vprot(LATCH) < VLATCH < Voc(LATCH)
−85
−80
−75
μA
Ven(LATCH)
enable voltage on pin LATCH
at start-up
1.30
1.35
1.40
V
Vhys(LATCH)
hysteresis voltage on pin
LATCH
Ven(LATCH) − Vprot(LATCH)
80
100
140
mV
Voc(LATCH)
open-circuit voltage on pin
LATCH
2.65
2.9
3.15
V
Temperature protection
Tpl(IC)
IC protection level temperature
130
140
150
°C
Tpl(IC)hys
hysteresis of IC protection level
temperature
-
10
-
°C
[1]
For a typical application with a compensation network on pin PFCCOMP, like the example in Figure 3.
[2]
Minimum required voltage change time for valley recognition on pin PFCAUX.
[3]
Minimum time required between demagnetization detection and ΔV/Δt = 0 on pin PFCAUX.
[4]
Hysteresis for PFC on/off control.
[5]
Guaranteed by design.
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
24 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
11. Application information
A power supply with the TEA1751(L)T consists of a power factor correction circuit
followed by a flyback converter. See Figure 16.
Capacitor CVCC buffers the IC supply voltage, which is powered via the high voltage
rectified mains during start-up and via the auxiliary winding of the flyback converter during
operation. Sense resistors RSENSE1 and RSENSE2 convert the current through the
MOSFETs S1 and S2 into a voltage at pins PFCSENSE and FBSENSE. The values of
RSENSE1 and RSENSE2 define the maximum primary peak current in MOSFETs S1 and S2.
In the example given, the LATCH pin is connected to a Negative Temperature Coefficient
V prot ( LATCH )
(NTC) resistor. When the resistance drops below ------------------------------- = 15.6 kΩ (typ), the
I O ( LATCH )
protection is activated. A capacitor CTIMEOUT is connected to the FBCTRL pin. For a
120 nF capacitor, typically after 10 ms the time-out protection is activated. RLOOP is added
so that the time-out capacitor does not interfere with the normal regulation loop.
RS1 and RS2 are added to prevent the soft start capacitors from being charged during
normal operation due to negative voltage spikes across the sense resistors.
Resistor RAUX1 is added to protect the IC from damage during lightning events.
D1
Cbus
S1
CSS1
RSS1
D2
T2
COUT
RSENSE1
RAUX1
RS1
12
8
S2
11
9 16 13
RS2
RSS2
10
COMPENSATION
6
CSS2
RSENSE2
TEA1751(L)T
RAUX2
7
4
1
3
2
RLOOP
5
CVCC
Θ
CTIMEOUT
014aaa302
Fig 17. Typical application diagram TEA1751(L)T
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
25 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
12. Package outline
SO16: plastic small outline package; 16 leads; body width 3.9 mm
SOT109-1
D
E
A
X
c
y
HE
v M A
Z
16
9
Q
A2
A
(A 3)
A1
pin 1 index
θ
Lp
1
L
8
e
0
detail X
w M
bp
2.5
5 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D (1)
E (1)
e
HE
L
Lp
Q
v
w
y
Z (1)
mm
1.75
0.25
0.10
1.45
1.25
0.25
0.49
0.36
0.25
0.19
10.0
9.8
4.0
3.8
1.27
6.2
5.8
1.05
1.0
0.4
0.7
0.6
0.25
0.25
0.1
0.7
0.3
0.01
0.019 0.0100 0.39
0.014 0.0075 0.38
0.039
0.016
0.028
0.020
inches
0.010 0.057
0.069
0.004 0.049
0.16
0.15
0.05
0.244
0.041
0.228
0.01
0.01
0.028
0.004
0.012
θ
o
8
o
0
Note
1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included.
REFERENCES
OUTLINE
VERSION
IEC
JEDEC
SOT109-1
076E07
MS-012
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-12-27
03-02-19
Fig 18. Package outline SOT109-1 (SO16)
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
26 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
13. Revision history
Table 6.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
TEA1751T_LT_2
20091223
Product data sheet
-
TEA1751T_LT_1
Modifications:
TEA1751T_LT_1
•
Value for junction temperature (Tj) changed in Table 3.
20090210
Product data sheet
TEA1751T_LT_2
Product data sheet
-
-
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
27 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
14. Legal information
14.1 Data sheet status
Document status[1][2]
Product status[3]
Objective [short] data sheet
Development
This document contains data from the objective specification for product development.
Preliminary [short] data sheet
Qualification
This document contains data from the preliminary specification.
Product [short] data sheet
Production
This document contains the product specification.
Definition
[1]
Please consult the most recently issued document before initiating or completing a design.
[2]
The term ‘short data sheet’ is explained in section “Definitions”.
[3]
The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status
information is available on the Internet at URL http://www.nxp.com.
14.2 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences of
use of such information.
Short data sheet — A short data sheet is an extract from a full data sheet
with the same product type number(s) and title. A short data sheet is intended
for quick reference only and should not be relied upon to contain detailed and
full information. For detailed and full information see the relevant full data
sheet, which is available on request via the local NXP Semiconductors sales
office. In case of any inconsistency or conflict with the short data sheet, the
full data sheet shall prevail.
14.3 Disclaimers
General — Information in this document is believed to be accurate and
reliable. However, NXP Semiconductors does not give any representations or
warranties, expressed or implied, as to the accuracy or completeness of such
information and shall have no liability for the consequences of use of such
information.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in medical, military, aircraft,
space or life support equipment, nor in applications where failure or
malfunction of an NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors accepts no liability for inclusion and/or use of
NXP Semiconductors products in such equipment or applications and
therefore such inclusion and/or use is at the customer’s own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) may cause permanent
damage to the device. Limiting values are stress ratings only and operation of
the device at these or any other conditions above those given in the
Characteristics sections of this document is not implied. Exposure to limiting
values for extended periods may affect device reliability.
Terms and conditions of sale — NXP Semiconductors products are sold
subject to the general terms and conditions of commercial sale, as published
at http://www.nxp.com/profile/terms, including those pertaining to warranty,
intellectual property rights infringement and limitation of liability, unless
explicitly otherwise agreed to in writing by NXP Semiconductors. In case of
any inconsistency or conflict between information in this document and such
terms and conditions, the latter will prevail.
No offer to sell or license — Nothing in this document may be interpreted or
construed as an offer to sell products that is open for acceptance or the grant,
conveyance or implication of any license under any copyrights, patents or
other industrial or intellectual property rights.
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from national authorities.
14.4 Trademarks
Notice: All referenced brands, product names, service names and trademarks
are the property of their respective owners.
GreenChip — is a trademark of NXP B.V.
15. Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
TEA1751T_LT_2
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 02 — 23 December 2009
28 of 29
TEA1751T; TEA1751LT
NXP Semiconductors
GreenChip III SMPS control IC
16. Contents
1
2
2.1
2.2
2.3
2.4
2.5
3
4
5
6
6.1
6.2
7
7.1
7.1.1
7.1.2
7.1.3
7.1.4
7.1.5
7.2
7.2.1
7.2.2
7.2.3
7.2.4
7.2.5
7.2.6
7.2.7
7.2.8
7.2.9
7.2.10
7.2.11
7.2.12
7.3
7.3.1
7.3.2
7.3.3
7.3.4
7.3.5
7.3.6
7.3.7
7.3.8
7.3.9
General description . . . . . . . . . . . . . . . . . . . . . . 1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Distinctive features . . . . . . . . . . . . . . . . . . . . . . 1
Green features . . . . . . . . . . . . . . . . . . . . . . . . . 1
PFC green features . . . . . . . . . . . . . . . . . . . . . 2
Flyback green features . . . . . . . . . . . . . . . . . . . 2
Protection features . . . . . . . . . . . . . . . . . . . . . . 2
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pinning information . . . . . . . . . . . . . . . . . . . . . . 4
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4
Functional description . . . . . . . . . . . . . . . . . . . 5
General control . . . . . . . . . . . . . . . . . . . . . . . . . 5
Start-up and UnderVoltage LockOut
(UVLO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Supply management. . . . . . . . . . . . . . . . . . . . . 7
Latch input . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Fast latch reset . . . . . . . . . . . . . . . . . . . . . . . . . 8
Overtemperature protection . . . . . . . . . . . . . . . 8
Power factor correction circuit . . . . . . . . . . . . . 8
ton control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Valley switching and demagnetization
(PFCAUX pin) . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Frequency limitation . . . . . . . . . . . . . . . . . . . . . 9
Mains voltage compensation
(VINSENSE pin) . . . . . . . . . . . . . . . . . . . . . . . . 9
Soft start-up (pin PFCSENSE) . . . . . . . . . . . . . 9
Low power mode . . . . . . . . . . . . . . . . . . . . . . 10
Dual boost PFC . . . . . . . . . . . . . . . . . . . . . . . 10
Overcurrent protection (PFCSENSE pin) . . . . 11
Mains undervoltage lockout / brownout
protection (VINSENSE pin) . . . . . . . . . . . . . . 11
Overvoltage protection (VOSENSE pin) . . . . . 11
PFC open loop protection (VOSENSE pin) . . 11
Driver (pin PFCDRIVER) . . . . . . . . . . . . . . . . 11
Flyback controller . . . . . . . . . . . . . . . . . . . . . . 12
Multimode operation . . . . . . . . . . . . . . . . . . . . 12
Valley switching (HV pin) . . . . . . . . . . . . . . . . 13
Current mode control (FBSENSE pin) . . . . . . 14
Demagnetization (FBAUX pin) . . . . . . . . . . . . 15
Flyback control / time-out (FBCTRL pin) . . . . 15
Soft start-up (pin FBSENSE) . . . . . . . . . . . . . 17
Maximum on-time . . . . . . . . . . . . . . . . . . . . . . 17
Overvoltage protection (FBAUX pin) . . . . . . . 17
Overcurrent protection (FBSENSE pin) . . . . . 18
7.3.10
7.3.11
8
9
10
11
12
13
14
14.1
14.2
14.3
14.4
15
16
Overpower protection. . . . . . . . . . . . . . . . . . .
Driver (pin FBDRIVER) . . . . . . . . . . . . . . . . .
Limiting values . . . . . . . . . . . . . . . . . . . . . . . .
Thermal characteristics . . . . . . . . . . . . . . . . .
Characteristics . . . . . . . . . . . . . . . . . . . . . . . .
Application information . . . . . . . . . . . . . . . . .
Package outline. . . . . . . . . . . . . . . . . . . . . . . .
Revision history . . . . . . . . . . . . . . . . . . . . . . .
Legal information . . . . . . . . . . . . . . . . . . . . . .
Data sheet status . . . . . . . . . . . . . . . . . . . . . .
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . .
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . .
Contact information . . . . . . . . . . . . . . . . . . . .
Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
19
19
20
20
25
26
27
28
28
28
28
28
28
29
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
© NXP B.V. 2009.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
Date of release: 23 December 2009
Document identifier: TEA1751T_LT_2