Sanyo VPC-J2 Service Manual

Also see for VPC-J2: Instruction manual

Contents

– 4 –1-3. PW1 POWER CIRCUIT DESCRIPTION1. OutlineThis is the main power circuit, and is comprised of the follow-ing blocks.Switching power controller (IC501)Analog system power output (Q5001, T5001)Digital 1.8 V power output (Q5011, L5007)Digital 3.3 V power output (Q5010, L5005)LED backlight power output (Q5015, L5010)5 V system power output (Q5018, L5017)2. Switching ControllerThis is the basic circuit which is necessary for controlling thepower supply for a PWM-type switching regulator, and is pro-vided with five built-in channels, only CH1 (analog systempower output), CH2 (digital 3.3 V system power output), CH3(digital 1.8 V system power output), CH4 (LED back light poweroutput) and CH5 (5 V system power output) are used. Feed-back from 15.0 V (A) (CH1), 3.3 V (D) (CH2), 1.8 V (D) (CH3),LED backlight output (CH4) and 5 V (CH5) power supply out-puts are received, and the PWM duty is varied so that eachone is maintained at the correct voltage setting level.2-1. Short-circuit ProtectionIf output is short-circuited for the length of time determinedby the condenser which is connected to Pin (27) of IC501, alloutput is turned off. The control signal (P ON) are recontrolledto restore output.3. Analog System Power Output15.0 V (A) and -7.6 V (A) are output. Feedback for the 15.0 V(A) is provided to the switching controller (Pin (23) of IC501)so that PWM control can be carried out.4. Digital 1.8 V Power Output1.8 V (D) is output. Feedback for the 1.8 V (D) is provided tothe switching controller (Pins (15) of IC501) so that PWM con-trol can be carried out.5. Digital 3.3 V Power Output3.3 V (D) is output. Feedback for the 3.3 V (D) is provided tothe swiching controller (Pin (42) of IC501) so that PWM con-trol can be carried out.6. LED Backlight Power OutputA constant current flows to the backlight LEDs. Feedback forthe voltage of R5057 is provided to the power controller (Pin(18) of IC501) so that PWM control can be carried out.7. 5 V System Power Output5 V is output. Feedback for the 5 V is provided to the swichingcontroller (Pin (39) of IC501) so that PWM control can becarried out.