sk540-ramps

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Some calculations

time to charge a capacitor:
t = -ln(1-Uc/Ucharge)*RC

Uc = 1V
Ucharge = 5V

so we have t = 0.22314355 * RC

horizontal ramp: 64uS -> 0.0000064 = 0.22314355 * RC
RC = 0.00028681088753
47nF, 6.1 kOhms
vertical ramp: 20 ms (1 field) -> 0.02 = 0.22314355 * RC
RC = 0.08962840235449
10uF , 8.9 kOhms -> 10k pot

does not work: ATTENTION the 4053 can have up to 2k5 Ohms ON resistance. we have to discharge the cap in max 9uS – length of h-sync + back porch
0.000009 = 0.22314355 * 2500 *C -> 16nF max
4n7/61k

also: the v-ramp we want to charge only on h-sync, so that’s 313 pulses of 10.4 uS, total charge time of 3.255 ms. Discharge in max 0.5ms.
discharge: 0.0005 = 0.22314355 * 2500 *C -> max 890nF
charge: 0.003255 = 0.22314355 * R * 100nF, R = 145.8k

Module Info

Inputs:
Outputs:
Power Draw on +5V: N/A
Power Draw on -5V: N/A
Frequency Response:

Schematic & PCB

View on Github

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