Ic Description; Analog Board - Philips DVDR3355 Service Manual

8.4

IC Description

8.4.1

Analog Board

IC7421 - SMPS Control IC
BLOCK DIAGRAM
1
V CC
M-level
S1
2
GND
3
−1
CTRL
2.5 V
burst
detect
TEA1507
PIN DESCRIPTION AND CONFIGURATION
SYMBOL PIN
V 1 supply voltage
CC
GND 2 ground
CTRL 3 control input
DEM 4 input from auxiliary winding for
demagnetization timing, OVP and OPP
I 5 programmable current sense input
sense
DRIVER 6 gate driver output
HVS 7 high voltage safety spacer, not
connected
DRAIN 8 drain of external MOS switch, input for
start-up current and valley sensing
Circuit- and IC description
SUPPLY
MANAGEMENT
internal UVLO start
supply
VOLTAGE
CONTROLLED
OSCILLATOR
FREQUENCY
CONTROL
OVER-
TEMPERATURE
PROTECTION
POWER-ON
RESET
UVLO
MAXIMUM
ON-TIME
PROTECTION
DESCRIPTION
3139 785 30981
START-UP
CURRENT SOURCE
VALLEY
LOGIC
100 mV
LOGIC DRIVER
LEB
S Q
blank
R Q
OCP
short
winding
Figure 8-6
handbook, halfpage
V CC
GND
CTRL
DEM
Fig.3 Pin configuration.
8.
clamp
OVER-
VOLTAGE
PROTECTION
I ss
0.5 V
soft
start
S2
0.75 V
OVERPOWER
PROTECTION
1 8 DRAIN
2 7 HVS
TEA1507
3 6 DRIVER
4 5 I sense
MGU231
EN 59
8
DRAIN
HVS
7
n.c.
4
DEM
6
DRIVER
5
I sense
MGU230