Read Sony CPD-G420 / CPD-G420S / CPD-G520 / GDM-F520 Service Manual online
CR1 chassis (E)
8
3-2. POWER SUPPLY PART
3-2-1. SYSTEM CONFIGURATION
This system is a two-converter power supply that provides the standby 1W feature.
The system consists of total eight blocks.
"AC Filter" ... Reduces noise in the power line and limits rush current at AC power ON.
"Power Factor Improving Circuit" ... Comprises a step-up chopper circuit to improve the power factor.
It controls the voltage of AC smoothing capacitor C610 to about 370 V.
"Sub Converter" ... Supplies standby 5 V, 3.3 V, USB voltage, heater voltage, and Vcc for the "Main Converter" and "Power Factor
Improving Circuit". It operates when AC is entered.
"Main Converter" ... Outputs +B, +B2, and (15 V.
"Degauss Circuit" ... Performs degaussing by the Degauss signal from the micro controller.
"ON/OFF Circuit" ... Turns on/off the "Main Converter" and "Power Factor Improving Circuit" by the Power signal from the micro
controller.
"Standby Output Circuit" ... Outputs standby 5 V.
It controls 3.3 V by the Power signal from the micro controller.
"Heater Circuit" ... Controls the heater voltage by the Power signal from the micro controller.
The relation between each state and signals from micro controller is as listed in table.
One-stage power saving
MODE
Power SW
Sub Converter
Main Converter
Heater Voltage
Signal
& Power Factor
ImprovingCircuit
Both Hsync and Vsync
Power ON
ON
ON
ON
5 V
Either Hsync or Vsync
Active off
OFF
ON
OFF
0 V
Neither Hsync and Vsync
Active off
OFF
ON
OFF
0 V
3-2-2. OPERATIONAL DESCRIPTION OF EACH BLOCK
3-2-2-1. AC Filter
AC is entered to the CN602 from the inlet filter, and passes through the AC filter consisting of a fuse F601, C601, T601, C602, etc. and
the TH601, and then it is supplied to the rectifying circuit comprising a rectifying diode D610 and an electrolytic capacitor C610.
The power thermistor TH601 operates to limit rush current at the AC power ON.
This TH601 is shorted by RY602, and in normal operation, the current does not flow.
The RY602 operates when Vcc is supplied by the "ON/OFF Circuit" described later.
The "Sub Converter" operates when AC is supplied.
3-2-2-2. Power Factor Improving Circuit
The IC610 contains a control circuit, switching MOSFET, and diodes.
This IC610 and L610 compose a step-up chopper circuit.
The output is regulated to about 370 V and charged in the C610.
In the voltage over 250 VAC, the input voltage is higher than the output voltage, and therefore this circuit does not operate.
The OVP circuit is built in this IC. The latch stops if the output voltage exceeds 450 V.
Click on the first or last page to see other CPD-G420 / CPD-G420S / CPD-G520 / GDM-F520 service manuals if exist.