Application Hints
STV8172A
CS performs an integration of the parabolic signal on CL, therefore the amount of S correction is set
by the combination of CL and Cs.
4.3 Application with Differential-output Drivers
Certain driver ICs provide the ramp signal in differential form, as two current sources i+ and i− with
opposite variations.
Figure 7: Using a Differential-output Driver
0 470µF 0 0 0 0 0 0 0 0 00.1µF
CF (47 to 100µF)
+Vs Output
Voltage
Differential output
driver IC
ip
+
icm
0R7 0 0 0 0
icm
-ip -
6
Power
Amplifier
7+
1-
3
2
Flyback
Generator
Output
Current
Ip
Thermal
Safety
5
1.5Ω Rd(*)
Yoke
Ly
4
-VEE
470µF00 00 00 00 00 00 00 00 00 00 0.1µF
R2
(*) recommended:
5----0L----µy---s-- < Rd < 2----0L----µy----s-
0000000000 R1
Let us set some definitions:
● icm is the common-mode current: icm = 12-- (i+ + i-)
● at peak of signal, i+ = icm + ip and i− = icm - ip, therefore the peak differential signal is ip - (-
ip) = 2 ip, and the peak-peak differential signal, 4ip.
The application is described in Figure 7 with DC yoke coupling. The calculations still rely on the fact
that V1 remains equal to V7.
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