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CR1 chassis (E)
7
3-1-4. Vertical deflection circuit
Vertical deflection is made in the deflection circuit using IC401. The IC401 is a kind of power OP-AMP. The IC401 detects V-DY
winding current, and controls the V-DY winding current so that it is similar to the "VSAWN" signal outputted from the D/A board.
3-1-5. Dynamic focus
Dynamic focus is grouped into horizontal focus (HDF) and vertical focus (VDF). These control waveforms are outputted from the D/
A board, and the D board only amplifies the amplitude. The amplified focus signals are synthesized by a fly-back transformer and
become CRT focus signal.
3-1-6. Rotation amplifier: IC703
The rotation amplifier is simply a DC control AMP. It amplifies the control voltage sent from the D/A board.
3-1-7. Digital convergence drive circuit system block diagram (extracted)
A block diagram of digital convergence drive circuit system is shown in <Fig. 3>.
INPUT
+15 V
–15 V
–15 V
GND
POWER
REF POWER
ON/OFF SWITCH
REF DC
3.3 V
DIGITAL CONVERGENCE
CONTROL
CONTROL
XSC
YSC
YSC
XDC
YDC
YDC
CY
PWR SW1
3.3 V
REF DC
XDC
YDC
POWER SWITCH
XSC
YSC
POWER OP AMP
IC 701
HIGH-SPEED
POWER OP AMP
POWER OP AMP
IC 702
From DSP
XSC
YSC
YSC
XDC
YDC
YDC
<Fig. 3>
3-1-8. Digital convergence amplifier: IC701, IC702
Digital convergence drive circuit is composed of a power operational amplifier (IC701) for static convergence (XSC/YSC) and a high
speed power operational amplifier (IC702) for dynamic convergence (XDC/YDC).
These control voltages are supplied from the DSP (IC1101) mounted on the DA board. The DSP is controlled by the micro controller
through the IIC bus.
The reference voltage for static convergence is generated from 3.3 V through the resistance division.
The reference voltage for dynamic convergence is supplied from the DSP (IC1101) on the DA board.
The high speed power operational amplifier (IC702) provides a switch terminal to control the ON/OFF of convergence by the
PWR_SW1.
3-1-9. High voltage control circuit
Fundamental circuit configuration is same as conventional (such as 21G1). As a control IC, IC901 (BA9758AFS) is used.
3-1-10. G2 voltage control circuit
About 1KV reference voltage for G2 control is generated using primary winding of the fly-back transformer. The IC902 controls this
voltage to attain the G2 control voltage.
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