6-13
BVM-D32E1WA/D32E1WE/D32E1WU
3. Main regulator
The separately excited current composite resonance system is used for the main regulator. The high
efficiency and low noise power regulation is realized. The main regulator consists mainly of IC210,
IC202, T201, C210, C211 and the secondary side rectifier circuit of T201. IC210 is a multiple chip
module in which the four chips of the control block, the FET drive block and the switching FET block
(high side and low side) are connected by bonding wire inside the IC. IC210 has the following circuit
configuration. A half-bridge rectifier is constructed by the two FET switches, the two capacitors C210
and C211, and the transformer T210 for the input voltage Vpfc. The secondary side of the transformer
has the center-tapped full wave rectifier. IC210 receives the control signal from IC202 that performs the
constant voltage control over the +135 V line through the isolator PH210. The control signal changes the
oscillating frequency of IC210 so that the constant voltage control is realized.
The secondary side of T201 generates not only +135 V but also +15 V, -15 V, +6 V and -6 V powers that
are required by the respective circuits.
4. Over-voltage protection circuit and over-current protection circuit
The respective voltage lines of the main power supply and the STBY5V line of the standby power supply
have the over-current protection circuit that protects the power supply when an abnormality occurs in the
respective loads. The +135 V line and the STBY55V line have the over-current protection circuit that
protects the power supplies and the loads when an abnormality occurs in the voltage feedback system.
The standby power supply detects the over-current by IC802 (4/4) and detects over-voltage by IC802 (2/
4). When the over-current or over-voltage is detected, oscillation of IC101 is stopped by the latch circuit
Q101 and Q102 through the isolator PH801.
When the main power supply has an abnormality, Q901 is turned on, and Q5 and Q6 are turned off
through the isolator PH901 so that the main power supply is stopped of its operation by turning off the
Vcc power that is supplied to IC1 and IC201. The protector mode is notified to the CPU on the E board
using the encoder/latch circuit that consists of Q801 through Q813.
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