TI UCC3810DWTR

UCC2810
UCC3810
www.ti.com
SLUS162D – FEBRUARY 1999 – REVISED FEBRUARY 2007
DUAL CHANNEL SYNCHRONIZED CURRENT-MODE PWM
FEATURES
•
•
•
•
•
•
•
•
•
•
DESCRIPTION
Single Oscillator Synchronizes Two PWMs
150-µA Startup Supply Current
2-mA Operating Supply Current
Operation to 1 MHz
Internal Soft-Start
Full-Cycle Fault Restart
Internal Leading-Edge Blanking of the Current
Sense Signal
1-A Totem Pole Outputs
75-ns Typical Response from Current Sense
to Output
1.5% Tolerance Voltage Reference
N PACKAGE
(TOP VIEW)
SYNC
CT
RT
FB1
COMP1
CS1
OUT1
GND
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
VCC
REF
ENABLE2
FB2
COMP2
CS2
OUT2
PWRGND
The UCC3810 is a high-speed BiCMOS controller
integrating two synchronized pulse width modulators
for use in off-line and dc-to-dc power supplies. The
UCC3810 family provides perfect synchronization
between two PWMs by usin g the same oscillator.
The oscillator’s sawtooth waveform can be used for
slope compensation if required.
Using a toggle flip-flop to alternate between
modulators, the UCC3810 ensures that one PWM
does not slave, interfere, or otherwise affect the
other PWM. This toggle flip- flop also ensures that
each PWM is limited to 50% maximum duty cycle,
insuring adequate off-time to reset magnetic
elements. This device contains many of the same
elements of the UC3842 current mode controller
family, combined with the enhancements of the
UCC3802. This minimizes power supply parts count.
Enhancements include leading edge blanking of the
current sense signals, full cycle fault restart, CMOS
output drivers, and outputs which remain low even
when the supply voltage is removed.
PW PACKAGE
(TOP VIEW)
SYNC
CT
RT
FB1
COMP1
CS1
OUT1
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VCC
REF
ENABLE2
FB2
COMP2
CS2
OUT2
PWRGND
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 1999–2007, Texas Instruments Incorporated
UCC2810
UCC3810
www.ti.com
SLUS162D – FEBRUARY 1999 – REVISED FEBRUARY 2007
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
ORDERING INFORMATION
PACKAGED DEVICES (1)
TJ
(1)
SOP (DW)
PDIP (N)
–40°C to 85°C
UCC2810DW (16)
UCC2810N (16)
0°C to 70°C
UCC3810DW (16)
UCC3810N (16)
All packages are available taped and reeled (indicated by the R suffix on the device type e.g.,
UCC2810JR)
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted) (1) (2)
UNIT
voltage (3)
VCC
Supply
ICC
Supply current
11V
20mA
Output peak current, OUT1, OUT2, 5% duty cycle
±1A
Output energy, OUT1, OUT2, capacitive load 20 µJ
20µJ
Analog inputs, FB1, FB2, CS1, CS2, SYNC
TJ
Operating junction temperature
Tstg
Storage temperature range
–0.3 to 6.3V
150°C
–65 to 150°C
Lead temperature (soldering, 10 sec)
(1)
(2)
(3)
300°C
Currents are positive into, negative out of the specified terminal. All voltages are with respect to GND.
Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
In normal operation, VCC is powered through a current-limiting resistor. Absolute maximum of 11 V applies when driven from a low
impedance such that the VCC current does not exceed 20 mA.
BLOCK DIAGRAM
REF
FB1
COMP1
CS1
CS2
VCC
15
15
5
6
11
16
Leading
Edge
Blanking
Leading
Edge
Blanking
Over-Current
Comparator
1.5 V
VCC OK
12.5 V
2.5 V
VCC
S Q
Error
Amp 1
55 kW
Voltage
Ref
REF OK
S Q
100 kW
7
OUT1
10
OUT2
R
1V
R
4V
0.5 V
S Q
R
Error
Amp 2
2.5 V
Full Cycle
Soft Start
+
−
S Q
R
R
55 kW
τ − 5ms
100 kW
35 mA
2
1V
Oscillator
13
12
1
2
3
14
9
8
FB2
COMP2
SYNC
CT
RT
ENABLES
PWRGND
GND
VDG−92062−1
2
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UCC2810
UCC3810
www.ti.com
SLUS162D – FEBRUARY 1999 – REVISED FEBRUARY 2007
ELECTRICAL CHARACTERISTICS
All parameters are the same for both channels, –40°C ≤ TA ≤ 85°C for the UCC2810, 0°C ≤ TA ≤ 70°C for the UCC3810,
VCC = 10 V (1) ; RT = 150 kΩ, CT = 120 pF; no load; TA = TJ; (unless otherwise specified)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
4.925
5.000
5.075
4.85
5.00
5.10
5
30
UNIT
REFERENCE
VCC
TJ = 25°C
Output voltage
IO(SC)
TJ = full range, 0 mA ≤ IREF ≤ 5 mA
Load regulation
0 mA ≤ IREF ≤ 5 mA
Line regulation
UVLO stop threshold voltage,
0.5 V ≤ VCC ≤ VSHUNT
Output noise voltage (2)
10Hz <f< 10 kHz,
TJ = 25°C
Long term stability (2)
TA = 125°C,
1000 hours
mV
12
Output short circuit current
V
235
µV
5
mV
-8
-25
mA
OSCILLATOR
fOSC
Oscillator frequency (3)
RT = 30 kΩ,
CT = 120 pF
860
980
1100
RT = 150 kΩ,
CT = 120 pF
190
220
250
Temperature stability (2)
kHz
2.5%
Peak voltage
2.5
Valley voltage
0.05
Peak-to-peak amplitude
SYNC threshold voltage
SYNC input current
2.25
2.45
2.65
0.80
1.65
2.20
SYNC = 5 V
30
V
µA
ERROR AMPLIFIER
VFB
FB input voltage
IFB
FB input bias current
COMP = 2.5 V
2.44
Open loop voltage gain
60
2.50
2.56
V
±1
µA
73
dB
2
MHz
fGAIN
Unity gain bandwidth (2)
ISINK
Sink current, COMP
FB = 2.7 V,
COMP = 1 V
0.3
1.4
3.5
ISRCE
Source current, COMP
FB = 1.8 V,
COMP = 4 V
-0.2
-0.5
-0.8
Minimum duty cycle
COMP = 0 V
Soft-start rise time, COMP
FB = 1.8 V,
Rise from 0.5 V to (REF – 1.5 V)
mA
0%
5
ms
CURRENT SENSE
Gain (4)
Maximum input
ICS
signal (5)
COMP = 5 V
1.20
1.55
0.9
1.0
Input bias current, CS
CS steps from 0 V to 1.2 V,
COMP = 2.5 V
Propagation delay time (CS to OUT)
COMP-to-CS offset voltage
CS = 0 V
V
nA
ns
1.35
1.55
1.85
0.45
0.90
1.35
V
For UCC3810, adjust VCC above the start threshold before setting at 10 V.
Ensured by design. Not production tested.
fOSC =
Oscillator frequency is twice the output frequency.
A=
(4)
(5)
(6)
1.1
±200
55
Overcurrent threshold voltage, CS
(3)
V/V
75
Blank time, CS (6)
(1)
(2)
1.80
4
RT ´ CT
DVCOMP
DVCS
Current sense gain A is defined by:
, 0 V ≤ VCS ≤ 0.8 V.
Parameter measured at trip point of latch with FB = 0 V.
CS blank time is measured as the difference between the minimum non-zero on-time and the CS-to-OUT delay.
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3
UCC2810
UCC3810
www.ti.com
SLUS162D – FEBRUARY 1999 – REVISED FEBRUARY 2007
ELECTRICAL CHARACTERISTICS (continued)
All parameters are the same for both channels, –40°C ≤ TA ≤ 85°C for the UCC2810, 0°C ≤ TA ≤ 70°C for the UCC3810,
VCC = 10 V ; RT = 150 kΩ, CT = 120 pF; no load; TA = TJ; (unless otherwise specified)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
PWM
Maximum duty cycle (2)
Minimum on-time
RT = 150 kΩ,
CT = 120 pF
45%
49%
50%
RT = 30 kΩ,
CT = 120 pF
40%
45%
48%
CS = 1.2 V,
COMP = 5 V
130
ns
OUTPUT
VOL
Low-level output voltage
IOUT = 20 mA
0.12
0.42
IOUT = 200 mA
0.48
1.10
0.7
1.2
IOUT = –20 mA
0.15
0.42
IOUT = –200 mA
1.2
2.3
IOUT = 20 mA,
VCC = 0 V
VOH
High-level output voltage (VCC – OUT)
tR
Rise time, OUT
COUT = 1 nF
20
50
tF
Fall time, OUT
COUT = 1 nF
30
60
V
ns
UNDERVOLTAGE LOCKOUT (UVLO)
Start threshold voltage
9.6
11.3
13.2
Stop threshold voltage
7.1
8.3
9.5
Start-to-stop hysteresis
ENABLE2 input bias current
ENABLE2 = 0 V
ENABLE2 input threshold voltage
V
1.7
3.0
4.7
-20
-35
-55
µA
0.80
1.53
2.00
V
0.15
0.25
2
3
OVERALL
Startup current
VCC < Start threshold voltage
Operating supply current, outputs off
VCC = 10 V,
FB = 2.75 V
VCC = 10 V,
CS = 0 V,
FB = 0 V,
RT = 150 kΩ
3.2
5.1
VCC = 10 V,
CS = 0 V,
FB = 0 V,
RT = 30 kΩ
8.5
14.5
11.0
12.9
14.0
0.4
1.2
Operating supply current, outputs on
VCC internal zener voltage
ICC = 10 mA
VCC internal zener voltage minus start
threshold voltage
4
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mA
V
UCC2810
UCC3810
www.ti.com
SLUS162D – FEBRUARY 1999 – REVISED FEBRUARY 2007
DEVICE INFORMATION
TERMINAL FUNCTIONS
TERMINAL
NAME
NO.
I/O
DESCRIPTION
COMP1
5
O
COMP2
12
O
CS1
6
I
CS2
11
I
CT
2
O
The timing capacitor of the oscillator. Recommended values of CT are between 100 pF and 1 nF.
Connect the timing capacitor directly across CT and GND.
ENABLE2
14
I
A logic input which disables PWM 2 when low. This input has no effect on PWM 1. This input is
internally pulled high. In most applications it can be left floating. In unusually noisy applications,
the input should be bypassed with a 1-nF ceramic capacitor. This input has TTL compatible
thresholds.
FB1
4
I
FB2
13
I
GND
8
–
OUT1
7
O
OUT2
10
O
PWRGND
9
–
To separate noise from the critical control circuits, this part has two different ground connections:
GND and PWRGND. GND and PWRGND must be electrically connected together.
REF
15
O
The output of the 5-V reference. Bypass REF to GND with a ceramic capacitor ≥ 0.01-µF for best
performance.
Low impedance output of the error amplifiers.
Current sense inputs to the PWM comparators. These inputs have leading edge blanking. For
most applications, no input filtering is required. Leading edge blanking disconnects the CS inputs
from all internal circuits for the first 55 ns of each PWM cycle. When used with very slow diodes or
in other applications where the current sense signal is unusually noisy, a small current-sense R-C
filter may be required.
The high impedance inverting inputs of the error amplifiers.
To separate noise from the critical control circuits, this part has two different ground connections:
GND and PWRGND. GND and PWRGND must be electrically connected together. However, use
care to avoid coupling noise into GND.
The high-current push-pull outputs of the PWM are intended to drive power MOSFET gates
through a small resistor. This resistor acts as both a current limiting resistor and as a damping
impedance to minimize ringing and overshoot.
RT
3
O
The oscillator charging current is set by the value of the resistor connected from RT to GND. This
pin is regulated to 1 V, but the actual charging current is 10 V/RT. Recommended values of RT
are between 10 kΩ and 470 kΩ. For a given frequency, higher timing resistors give higher
maximum duty cycle and slightly lower overall power consumption.
SYNC
1
I
This logic input can be used to synchronize the oscillator to a free running oscillator in another
part. This pin is edge triggered with TTL thresholds, and requires at least a 10-ns-wide pulse. If
unused, this pin can be grounded, open circuited, or connected to REF.
VCC
16
I
The power input to the device. This pin supplies current to all functions including the high current
output stages and the precision reference. Therefore, it is critical that VCC be directly bypassed to
PWRGND with an 0.1-µF ceramic capacitor.
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UCC2810
UCC3810
www.ti.com
SLUS162D – FEBRUARY 1999 – REVISED FEBRUARY 2007
APPLICATION INFORMATION
TIMING RESISTOR
Supply current decreases with increased RT by the relationship:
DI CC =
11V
RT
For more information, see the detailed oscillator block diagram.
LEADING EDGE BLANKING AND CURRENT SENSE
Figure 1 shows how an external power stage is connected to the UCC3810. The gate of an external power
N-channel MOSFET is connected to OUT through a small current-limiting resistor. For most applications, a 10-Ω
resistor is adequate to limit peak current and also practical at damping resonances between the gate driver and
the MOSFET input reactance. Long gate lead length increases gate capacitance and mandates a higher series
gate resistor to damp the R-L-C tank formed by the lead, the MOSFET input reactance, and the device’s driver
output resistance.
The UCC3810 features internal leading edge blanking of the current-sense signal on both current sense inputs.
The blank time starts when OUT rises and continues for 55 ns. During that 55 ns period, the signal on CS is
ignored. For most PWM applications, this means that the CS input can be connected to the current-sense
resistor as shown in Figure 1. However, high speed grounding practices and short lead lengths are still required
for good performance.
From
Oscillator
Over−Current
Comparator
1.5 V
Power
Stage
−
Soft
Start
+
S
R
+
CS
Current
Sense
Resistor
+
−
One
Shot
Q
Gate
Driver
OUT
R
−
PWM
PWM
Comparator Latch
Error
Amp
Figure 1. Detailed Block Diagram
OSCILLATOR
The UCC3810 oscillator generates a sawtooth wave at CT. The sawtooth rise time is set by the resistor from RT
to GND. Since RT is biased at 1 V, the current through RT is 1 V/RT. The actual charging current is 10 times
higher. The fall time is set by an internal transistor on-resistance of approximately 100 Ω. During the fall time, all
outputs are off and the maximum duty cycle is reduced to below 50%. Larger timing capacitors increase the
discharge time and reduce frequency. However, the percentage maximum duty cycle is only a function of the
timing resistor RT, and the internal 100-Ω discharge resistance.
ERROR AMPLIFIER OUTPUT STAGE
The UCC3810 error amplifiers are operational amplifiers with low-output resistance and high-input resistance.
The output stage of one error amplifier is shown in Figure 3. This output stage allows the error amplifier output
to swing close to GND and as high as one diode drop below 5 V with little loss in amplifier performance.
6
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UCC2810
UCC3810
www.ti.com
SLUS162D – FEBRUARY 1999 – REVISED FEBRUARY 2007
APPLICATION INFORMATION (continued)
VCC
0.2 V
+
−
I
1V
R
10I
+
Q
+
RON 9 100
−
2.5 V
S
−
One
Shot
3
1
2
RT
SYNC
RT
CT
Figure 2. Oscillator
5V
VCC
COMP
Figure 3. Error Amplifier Output Stage
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7
UCC2810
UCC3810
www.ti.com
SLUS162D – FEBRUARY 1999 – REVISED FEBRUARY 2007
TYPICAL CHARACTERISTICS
ERROR AMPLIFER GAIN AND PHASE
vs
FREQUENCY
OSCILLATOR FREQUENCY
vs
TIMING RESISTANCE
80
1M
60
90
Gain
20
45
0
0
−20
1k
10 k
100 k
1M
Phase − °
Gain − dB
Fhase
40
Oscillator Frequency − Hz
135
100 k
10 k
10 k
10 M
f − Frequency − Hz
100 k
RT − Timing Resistor − W
Figure 4.
Figure 5.
OSCILLATOR FREQUENCY
vs
TEMPERATURE
MAXIMUM DUTY CYCLE
vs
TIMING RESISTANCE
1.2
10 M
50
48
1.1
Duty Cycle − %
Oscillator Frequency − MHz
1.15
1.05
1
0.95
46
44
0.9
42
0.85
0.8
−55
−35 −15
5
25 45
65
TA − Temperature − C
85
105 125
40
10 k
Figure 6.
8
100 k
RT − Timing Resistor − W
Figure 7.
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1M
UCC2810
UCC3810
www.ti.com
SLUS162D – FEBRUARY 1999 – REVISED FEBRUARY 2007
TYPICAL CHARACTERISTICS (continued)
MAXIMUM DUTY CYCLE
vs
FREQUENCY
10
50
8
48
Duty Cycle − %
I CC − Input Current − mA
INPUT CURRENT
vs
OSCILLATOR FREQUENCY
6
Switching
4
2
44
42
Outputs Off
10 k
46
CT = 120 pF
100 k
1M
40
10 k
100 k
1M
f − Frequency − Hz
f − Frequency − Hz
Figure 8.
Figure 9.
DC
Input
+12 V OUT
+5 V OUT
0.1 mF
16
VCC
OPTO1
5 COMP1
OUT1 7
2
3
COMP
VCC
5 REF
4 FB1
UCC3810
OPTO2
4 E/A+
CS1 6
12 COMP2
0.1
OUT2 10
HV SUP
ENABLE
OPTO1
8
I
6 SENSE SET
UC39432
GND
7
13 FB2
TTL MONITOR
SYNC
0.1
COLL 1
CS2 11
High Voltage Out
(Monitor Raster)
1 SYNC
REF 15
14 ENABLE2
RT
3
PWR
CT GND GND
2
8
0.1
9
2
3
COMP
VCC
5 REF
4 E/A+
0.1
0.1
OPTO2
COLL 1
6 SENSE
UC39432
ISET 8
GND
7
VDG−94022
Figure 10. Typical Application
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9
PACKAGE MATERIALS INFORMATION
www.ti.com
30-Mar-2010
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
UCC2810DWTR
SOIC
DW
16
2000
330.0
16.4
10.85
10.8
2.7
12.0
16.0
Q1
UCC3810DWTR
SOIC
DW
16
2000
330.0
16.4
10.85
10.8
2.7
12.0
16.0
Q1
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
30-Mar-2010
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
UCC2810DWTR
SOIC
DW
16
2000
346.0
346.0
33.0
UCC3810DWTR
SOIC
DW
16
2000
346.0
346.0
33.0
Pack Materials-Page 2
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