BCD AP3710 Low power pwm controller for off-line adapter Datasheet

Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
General Description
Features
The AP3710 is a green-mode PWM controller, its main
applications are low power supplies such as offline
battery chargers, adapters, STB and other auxiliary
supplies, where the needs for low no load power, low
total cost and high reliability are all required.
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The functional blocks of AP3710 include: under voltage lockout with low start-up current; precise voltage
reference for internal comparators; PWM comparator
with current limit control, feedback signal and bandgap input; short circuit comparator and open circuit
protection for opto-coupler.
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The AP3710 operates at a fixed 60kHz switching frequency, its output connects to the emitter of high voltage NPN transistor or the source of MOSFET. In
normal mode, it works as a switch to turn on or turn off
the external transistor. In failure modes like open loop,
over voltage or overload due to short circuit, the chip
enters into an auto restart mode controlled by the internal protection unit.
AP3710
Current Mode Control with Skip Cycle Capability
Low Start-up Current: 0.25 mA
Low Operating Current: 0.45mA
Output Current Capacity: 900 mA
Fixed Switching Frequency: 60 kHz
Frequency Dithering for Low EMI
Under-Voltage Lockout with Hysteresis
Built-in Slope Compensation
Short Circuit Protection
Open and Short Circuit Protection for OptoCoupler
Maximum Input Power is 0.2W under No Load
Maximum Input Power is 1W under 0.5W Load
Low Total Cost Solution
Applications
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The AP3710 is available in SOIC-8 and DIP-8 packages.
Adapters
Battery Chargers
Set Top Boxes
Auxiliary Supplies
DVD
DIP-8
SOIC-8
Figure 1. Package Types of AP3710
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Pin Configuration
M/P Package
(SOIC-8/DIP-8)
GND
1
8
NC
VCC
2
7
VA
NC
3
6
NC
OUT
4
5
VSEN
Figure 2. Pin Configuration of AP3710 (Top View)
Pin Description
Pin Number
Pin Name
Function
1
GND
Power supply ground
2
VCC
The power supply of the IC and this terminal is also used for the feedback control
3, 6, 8
NC
4
OUT
The PWM output is directly connected to the emitter of NPN transistor or the source
of MOSFET
5
VSEN
It is used for line voltage compensation, and PWM uses this to terminate the output
switch conduction
7
VA
It is used for short circuit protection, and this terminal will be pulled down to low
level when short circuit happens at the load side
Not connected
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Functional Block Diagram
VCC
2
UVLO
COMPARATOR
4
START-UP
CURRENT
SOURCE
OUT
BIAS
-
VREF
(1.2V)
OSCILLATOR
+
PWM
COMPARATOR
FB
5
VSEN
VREF
(1.2V)
DISCHARGE
COMPARATOR
GND
1
VREF
(1.2V)
+
_
DRIVER
+
-
PWM
CONTROL
SLOP
COMPENSATION
7
VA
DISCHARGE
LOGIC
Figure 3. Functional Block Diagram of AP3710
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Ordering Information
AP3710
-
Circuit Type
E1: Lead Free
Package
TR: Tape and Reel
Blank: Tube
M: SOIC-8
P: DIP-8
Package
Switching Frequency
Temperature Range
SOIC-8
60kHz
-40 to 85oC
DIP-8
60kHz
-40 to 85oC
Part Number
Marking ID
Packing Type
AP3710M-E1
3710M-E1
Tube
AP3710MTR-E1
3710M-E1
Tape & Reel
AP3710P-E1
AP3710P-E1
Tube
BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant.
Absolute Maximum Ratings (Note 1)
Parameter
Value
Unit
Supply Voltage
-0.3 to 6.3
V
Voltage at OUT
-0.3 to 40
V
Analog Input at VSEN
-0.3 to 6.3
V
Internally limited
A
Power Dissipation
0.6
W
Operating Junction Temperature
150
o
Output Current at OUT
Storage Temperature
-65 to 150
C
oC
Lead Temperature (Soldering, 10s)
300
o
ESD (Machine Model)
300
V
C
Note 1: Stresses greater than 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 Ratings" for extended periods
may affect device reliability.
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Electrical Characteristics
(VCC=4V, TJ=25oC, unless otherwise specified.)
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
UVLO SECTION
Turn on Threshold Voltage
VCC (on)
5.30
5.60
5.90
V
Turn off Threshold Voltage
VCC (off)
3.4
3.65
3.90
V
VDIS
2.7
2.9
3.1
V
0.25
0.4
0.45
0.7
Discharge Voltage
STANDBY CURRENT SECTION
Start-up Current
IST
Operating Current
ICC(opr)
VCC Zener Voltage
VZ
Dynamic Impedance
VCC=4V
mA
ICC=10mA
6.5
7
7.5
V
RVCC
VCC=3.8 to 4.8V (Note 2)
10
18
30
kΩ
FSW
(Note 3)
50
60
70
kHz
±2
±3.5
±5
kHz
INTERNAL OSCILLATOR
Switching Frequency
Frequency Dithering
Temperature Stability
5
-40 to 85oC
%
DRIVE OUTPUT SECTION
OUT Turn-on Voltage
VOUT(on)
7.6
9.3
11
V
OUT Turn-off Voltage
VOUT(off)
5.7
6.8
7.9
V
Rise Time
TR
CL=1nF, 15Ω pull-up
60
Fall Time
TF
CL=1nF, 15Ω pull-up
30
Maximum Duty Cycle
DMAX
Minimum Duty Cycle
Driver OUT On-Resistance
ROUT
Switch Off Current (OUT)
Effective Current Limit
OUT Current Coefficient
ILIM
VCC(off) + 0.2V
68
ns
75
82
VCC=VCC (on)-0.2V
3
5
IOUT=0.7A
3
5
Ω
Driver off, VOUT=10V
20
40
µA
VCC=VCC(off)+0.5V
800
GA
%
900
mA
-0.6
A/V
CURRENT SECTION
Maximum Input Signal
VSEN
0.9
1.0
1.1
V
Note 2: Guaranteed by design, not tested in production.
Note 3: The fixed oscillation frequency, the frequency jittering is not included.
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Electrical Characteristics (Continued)
1N5819
L
70µH
R
100Ω/3W
+
C1
100µF/50V
+
C2
100µF/50V
+
_
27V Zener
VIN =10V
GND
OUT
AP3710
VCC
C3
2200pF
VCC=VCC(off)+0.5V
Figure 4. The Test Circuit for Current Limit
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Typical Performance Characteristics
400
680
360
600
320
560
Start-up Current (µA)
Operating Current (µA)
640
520
480
440
400
240
200
160
360
320
-40
280
120
-20
0
20
40
60
80
100
120
-40
-20
0
20
40
60
80
100
120
o
Ambient Temperature ( C)
o
Ambient Temperature ( C)
Figure 5. Operating Current vs. Ambient Temperature
Figure 6. Start-up Current vs. Ambient Temperature
500
70
68
Switching Frequency (KHz)
Start-up Current (µA)
400
300
200
100
66
64
62
60
58
56
0
1
2
3
4
-40
5
-20
0
20
40
60
80
100
120
o
Ambient Temperature ( C)
VCC Voltage (V)
Figure 7. Start-up Current vs. VCC Voltage
Figure 8. Switching Frequency vs. Ambient Temperature
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Typical Performance Characteristics (Continued)
1.10
3.10
3.05
3.00
Discharge Voltage (V)
Normalized Current Limit
1.05
1.00
0.95
0.90
2.95
2.90
2.85
2.80
0.85
2.75
0.80
-40
-20
0
20
40
60
80
100
2.70
-40
120
-20
0
20
40
60
80
100
120
o
o
Ambient Temperature ( C)
Ambient Temperature ( C)
Figure 10. Discharge Voltage vs. Ambient Temperature
Figure 9. Normalized Current Limit
vs. Ambient Temperature
5.5
4.0
Turn on Threshold Voltage (V)
3.8
3.6
On Resistance (Ω)
3.4
3.2
3.0
2.8
2.6
2.4
5.4
5.3
5.2
5.1
2.2
2.0
-40
-20
0
20
40
60
80
100
5.0
-40
120
-20
0
20
40
60
80
100
120
o
o
Ambient Temperature ( C)
Ambient Temperature ( C)
Figure 11. On Resistance vs. Ambient Temperature
Figure 12. Turn on Voltage vs. Ambient Temperature
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
VIN
Rectified AC
Function Description
VO
1. UVLO and Start up Circuit
The AP3710's turn on threshold voltage is 5.6V and its
turn off threshold voltage is 3.65V, so the UVLO
hysteresis voltage is 1.95V, which helps AP3710 to
draw adequate energy to supply VCC terminal during
start-up. Please see Figure 13 for UVLO chart.
D6
R2+R3
R5
Q1
APT13003
R13
U3
PC817
D6
R16
C7
R14
R8
ICC: Supply Current (µA)
R6
R7
OUT VSEN
VA
+
Turn off
Turn on
GND
C4
+
VCC
U2
AZ431
R16
C5
C6
U1
AP3710
Figure 14. The Start-up
Circuit of Typical Application
3.65 5.6
VCC: Supply Voltage (V)
In start-up section of typical application shown by
Figure 14, the rectified line voltage VIN charges the
capacitor C4 through start-up resistor R2+R3 until Q1
is turned on so OUT terminal can directly drive
external Q1, a MOSFET inside AP3710 is connected
in series with the Q1.
Figure 13. 5.6/3.65V UVLO
Threshold of AP3710
The VCC terminal in Figure 3 is used for both bias
supply and feedback control. When AP3710 is
powered on, the start-up current source turns on and it
can not turn off until VCC level increases to its
threshold value and PWM pulse is produced.
Once the start-up is set up, the auxiliary bias winding
will supply the VCC terminal enough operating
current. The start-up sequence is shown in Figure 15.
Figure 15. Power up Waveforms
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Function Description (Continued)
2. VCC/Feedback Control
5. Current Limit Control
In Figure 14, an opto-coupler and secondary constant
voltage consists of voltage feedback network. Voltage
feedback loop consists of shunt regulator AZ431 and
FB/VCC terminal of AP3710. When load is heavy, the
voltage on VCC terminal will decrease to enlarge duty
cycle; on the contrary, if load drops, the voltage on
VCC will increase to reduce duty cycle.
The AP3710 employs current mode control to
improve transient response and voltage stability. In
Figure 3, the external inductor current through the
OUT pin is converted to a voltage by an internal
resistor, and this voltage will participate to control
duty cycle and peak inductor current.
3. Skip Cycle Mode Operation
6. Frequency Dithering
The AP3710 enters skip cycle mode when load power
drops below a given level, and this is performed by
sensing the VCC voltage level, i.e., the heavier load
power, the lower VCC voltage level. In normal
operation, the VCC terminal indicates a peak
inductance current under certain load power. If the
load power decreases, VCC voltage level increases to
ask for less peak current. When it reaches a
determined value, the IC prevents the current from
decreasing further down and starts to blank the output
pulses, the IC then enters the skip cycle mode
operation. Figure 16 is the sketch for the two operation
mode.
Frequency dithering is performed by periodically
spreading a single switching frequency into adjacent
frequency band, so the peak energy is spread. This
technique can improve EMI performance by reducing
both quasi peak and average EMI emissions.
Normal
PWM
Waveform
Cycle Skip
Waveform
0
t
Figure 16. Skip Cycle and Normal PWM Waveform
Figure 17. Frequency Dither Influences
the Switching Cycle
4. Slope Compensation
The AP3710 is current mode PWM controller, and it
regulates peak inductance current by its current
control loop. It is known that a continuous condition
mode SMPS may induce noise and harmonic
oscillation on current sense or feedback signal, and
this is especially serious when duty cycle exceeds
50%. The internal slope compensation of AP3710 can
improve power supply stability by increasing the
current slope.
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Function Description (Continued)
7. Short Circuit Protection
From
UVLO
From
VCC
Internal short circuit control can protect a SMPS from
being damaged when short circuit at its output
happens.
Discharge
Comparator
VA
Discharge
Logic
In Figure 18, when VCC drops below its turn off
threshold value, the UVLO comparator's output will
control the Discharge Logic to pull VA terminal to low
level, and the low level is kept before the VCC voltage
drops below the threshold value of discharge comparator. Then the system will re-startup from C4 charging
again and the same process will repeat indefinitely.
The long start-up period makes the input power low
enough to ensure the whole system in safety under
output short circuit condition.
VREF
1.2V
Figure 18. Short Circuit Protection Block
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Typical Application
R1
D1-D4
R11 C11
T1
EE16
L2
J1
AC 85-264V
F1
R9
+
C1
+
L3
D8
C3
R4
+
C8
L4
C9
+
12V/1A
VO+
ZD2
C2
VO-
R2
D7
D5
R3
R5
R13
U3
Q1
R15
C7
R14
D6
R8
R6
R7
OUT VSEN
VCC
VA
+
C4
+
GND
U2
R16
C5
C10
C6
U1
Figure 19. 12V/1A Adapter
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Bill of Materials for Figure 19
Designator
R1
Part Type
Designator
Part Type
Resistor, NTC Resistor, 5Ω
C1, C2
Electrolytic Capacitor, 10 µF/400V, φ10
R2, R3
Resistor, 1MΩ, 1206
C3
Capacitor, 2200pF, d=5mm
R4
Resistor, 68kΩ, 1206
C4, C5
Capacitor, 10µF, d=4.5mm
R5
Resistor, 3Ω, 0805
C6
Capacitor, 22nF, 0805
R6
Resistor, 200Ω, 0805
C7
Capacitor, 0.47µF, 0805
R7
Resistor, 2kΩ, 0805
C8
Electrolytic Capacitor, 1000µF
R8
Resistor, 5.1MΩ, SIP
C9
Electrolytic Capacitor, 220µF
R9, R15, R16 Resistor, 3kΩ, 0805
C10
Y Capacitor, 2200pF
Resistor, 15 Ω, 1206
C11
Capacitor, 1nF, 0805
R13
Resistor, 1kΩ, 0805
Q1
Transistor, APT13003, TO126
R14
Resistor, 11.4kΩ, 0805
U3
Opto-coupler, PC817, DIP-4
D1 to D4
Diode, 1N4007, DO-41
L2
Inductor, 300µH/0.3A
D5, D6
Diode, 1N4148, LL-34
L4
Inductor, 100µH/1A
R11
D7
Diode, FR107, DO-15
ZD2
Zener, 13V/1W
D8
Diode, 3100, DO-201
T1
Transformer, EE-20
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Mechanical Dimensions
SOIC-8
4.700(0.185)
5.100(0.201)
7°
Unit: mm(inch)
0.320(0.013)
1.350(0.053)
1.750(0.069)
8°
8°
7°
0.675(0.027)
0.725(0.029)
D
5.800(0.228)
1.270(0.050)
6.200(0.244)
TYP
D
20:1
φ 0.800(0.031)
0.300(0.012)
R0.150(0.006)
0.100(0.004)
0.200(0.008)
0°
8°
1.000(0.039)
3.800(0.150)
4.000(0.157)
0.330(0.013)
0.190(0.007)
0.250(0.010)
1°
5°
0.510(0.020)
0.900(0.035)
R0.150(0.006)
0.450(0.017)
0.800(0.031)
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
LOW POWER PWM CONTROLLER FOR OFF-LINE ADAPTER
AP3710
Mechanical Dimensions (Continued)
DIP-8
Unit: mm(inch)
0.700(0.028)
7.620(0.300)TYP
1.524(0.060) TYP
6°
5°
6°
3.200(0.126)
3.600(0.142)
3.710(0.146)
4.310(0.170) 4°
4°
0.510(0.020)MIN
3.000(0.118)
3.600(0.142)
0.204(0.008)
0.360(0.014)
8.200(0.323)
9.400(0.370)
0.254(0.010)TYP
2.540(0.100) TYP
0.360(0.014)
0.560(0.022)
0.130(0.005)MIN
6.200(0.244)
6.600(0.260)
R0.750(0.030)
Φ3.000(0.118)
Depth
0.100(0.004)
0.200(0.008)
9.000(0.354)
9.400(0.370)
Nov. 2007 Rev. 1. 2
BCD Semiconductor Manufacturing Limited
15
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of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
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