TCL SERVICE MANUAL - Tecnicosaurios
TCL SERVICE MANUAL - Tecnicosaurios
TCL SERVICE MANUAL - Tecnicosaurios
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Application Hints<br />
STV8172A<br />
C S performs an integration of the parabolic signal on C L , therefore the amount of S correction is set<br />
by the combination of C L and C s .<br />
4.3 Application with Differential-output Drivers<br />
Certain driver ICs provide the ramp signal in differential form, as two current sources i + and i with<br />
opposite variations.<br />
Figure 7: Using a Differential-output Driver<br />
470µF<br />
0.1µF<br />
C F (47 to 100µF)<br />
+Vs<br />
Output<br />
Voltage<br />
Differential output<br />
driver IC<br />
-V EE<br />
Power<br />
Amplifier<br />
3 2<br />
Flyback<br />
Generator<br />
i p<br />
+<br />
7<br />
i cm<br />
+<br />
R 5<br />
7<br />
1 -<br />
Thermal<br />
Safety<br />
1.5<br />
-i<br />
i p -<br />
cm<br />
4<br />
6<br />
0.22µF<br />
Output<br />
Current<br />
Rd(*)<br />
I p<br />
Yoke<br />
Ly<br />
470µF<br />
0.1µF<br />
R 2<br />
R 1<br />
(*) recommended:<br />
Ly<br />
Ly<br />
------------- < Rd< -------------<br />
50s 20s<br />
Let us set some definitions:<br />
●<br />
i cm is the common-mode current:<br />
1<br />
i cm<br />
= --i <br />
2 +<br />
+ i -<br />
<br />
● at peak of signal, i + =i cm +i p and i =i cm -i p , therefore the peak differential signal is i p -(-<br />
i p )=2i p , and the peak-peak differential signal, 4i p .<br />
The application is described in Figure 7 with DC yoke coupling. The calculations still rely on the fact<br />
that V 1 remains equal to V 7 .<br />
8/14 STMicroelectronics Confidential
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