Service manual

Circuit Description
*. Function Block
A. Interface
1. Power Supply (DC/DC Converter)
ICM1 is a current mode switching regulator controller that drives an external N-channel
power MOSFET (ICM2) using a fixed frequency architecture (200KHz). It converts a 12V DC
input voltage into regulated and stable output voltage of 5V.
Pin2 (I
TH / RUN) provide a soft start point and run control inputs. During normal operation
the voltage on the I
TH / RUN pin will vary from 1.19V to 2.4V depending on the load current.
Pulling the I
TH / RUN pin up 0.8V(using CM5 and RM2) allows the ICM1 to begin operation.
Pin7 (Boost) supply to the topside Floating Drivers. The bootstrap capacitor (CM8) is
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VG800b
33
VG800b Block Diagram