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ViewSonic Corporation
Circuit Diagram
LD7552BS (IC901):
PWM control, high-voltage startup current. The circuit unit has
functions such as over-current protection, over-voltage protection, output short-circuit
protection and etc. The function of each pin and the inside circuit diagram are as
follows
:
Pin
Name
Function
1 GND Ground
2 COMP
Voltage feedback pin (same as the COMP pin in UC384X), By
connecting a photo-coupler to close the control loop and achieve the
regulation
3
VCC Supply voltage pin
4 RT
This pin is to program the switching frequency. By connecting a resistor
to ground to set the switching frequency.
6 NC
Unconnected
pin
7
VCC Supply voltage pin
8
OUT Gate drive output to drive the external MOSFET
Summary of Contents for VA712b-2
Page 11: ...11 ViewSonic Corporation 3 Front Panel Function Controls And Indicators...
Page 18: ...18 ViewSonic Corporation 4 2 POWER BLOCK FUNCTION DESCRIPTION Inverter Block Function...
Page 19: ...19 ViewSonic Corporation Power Block Function...
Page 26: ...26 ViewSonic Corporation...
Page 42: ...42 ViewSonic Corporation 3 3 DDC Key In Procedure Sep1 Select and execute DDC Key In program...
Page 43: ...43 ViewSonic Corporation Sep2 Inpute the S N and execute Enter...
Page 44: ...44 ViewSonic Corporation...
Page 45: ...45 ViewSonic Corporation Sep3 Key the Enter and write the data...
Page 46: ...46 ViewSonic Corporation Sep4 If ddc program OK and show data compare ok...
Page 47: ...47 ViewSonic Corporation 6 Trouble Shooting Flow Chart...
Page 66: ...66 ViewSonic Corporation 8 Exploded Diagram And Spare Parts List...
Page 67: ...67 ViewSonic Corporation...
Page 68: ...68 ViewSonic Corporation 5 7 Packing For Shipping...
Page 72: ...72 ViewSonic Corporation Picture 7 Picture 8 Picture 9 Picture 10 Picture 11 Picture 12...
Page 73: ...73 ViewSonic Corporation Picture 13 Picture 14 Picture 15...
Page 74: ...74 ViewSonic Corporation Picture 16 Picture 17 Picture 18 Picture 19 Picture 20...
Page 75: ...75 ViewSonic Corporation 10 Block Diagram...
Page 84: ...84 ViewSonic Corporation 12 PCB Layout Diagram 12 1 MAIN BOARD PCB TOP VIEW...
Page 85: ...85 ViewSonic Corporation...
Page 86: ...86 ViewSonic Corporation 12 2 MAIN BOARD PCB BUTTON VIEW...
Page 87: ...87 ViewSonic Corporation 12 3 KEYBOARD TOP VIEW 12 4 KEYBOARD BUTTON VIEW...
Page 88: ...88 ViewSonic Corporation 12 5 POWER PCB TOP VIEW...
Page 89: ...89 ViewSonic Corporation 12 6 POWER PCB BUTTON VIEW...
Page 90: ...90 ViewSonic Corporation 12 6 AUDIO PCB TOP VIEW BUTTON VIEW...