sk540-ramps
You are viewing an old revision of this post, from December 9, 2013 @ 17:05:54. See below for differences between this version and the current revision.
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
10k pot, 4k7 series and 10nF should do it
Module Info
Inputs: | |
---|---|
Outputs: | |
Power Draw on +5V: | N/A |
Power Draw on -5V: | N/A |
Frequency Response: |
Schematic & PCB
Observations
No observations yet
Revisions:
- December 10, 2013 @ 17:12:52 [Current Revision] by Michael
- December 10, 2013 @ 17:12:52 by Michael
- December 10, 2013 @ 16:56:51 by Michael
- December 9, 2013 @ 17:05:54 by Michael
- December 9, 2013 @ 16:56:27 by Michael
- December 9, 2013 @ 16:47:30 by Michael
- December 9, 2013 @ 16:31:44 by Michael
- December 7, 2013 @ 17:23:06 by Michael
- December 7, 2013 @ 15:51:52 by Michael
- December 7, 2013 @ 15:47:14 by Michael
- December 7, 2013 @ 15:37:32 by Michael
Changes:
December 9, 2013 @ 17:05:54 | Current Revision | ||
---|---|---|---|
Content | |||
Some calculations | Some calculations | ||
time to charge a capacitor: | time to charge a capacitor: | ||
t = -ln(1-Uc/Ucharge)*RC | t = -ln(1-Uc/Ucharge)*RC | ||
Uc = 1V | Uc = 1V | ||
Ucharge = 5V | Ucharge = 5V | ||
so we have t = 0.22314355 * RC | so we have t = 0.22314355 * RC | ||
horizontal ramp: 64uS -> 0.0000064 = 0.22314355 * RC | horizontal ramp: 64uS -> 0.0000064 = 0.22314355 * RC | ||
RC = 0.00028681088753 | RC = 0.00028681088753 | ||
47nF, 6.1 kOhms | 47nF, 6.1 kOhms | ||
vertical ramp: 20 ms (1 field) -> 0.02 = 0.22314355 * RC | vertical ramp: 20 ms (1 field) -> 0.02 = 0.22314355 * RC | ||
RC = 0.08962840235449 | RC = 0.08962840235449 | ||
10uF , 8.9 kOhms -> 10k pot | 10uF , 8.9 kOhms -> 10k pot | ||
does not work: <strong>ATTENTION the 4053 can have up to 2k5 Ohms ON resistance</strong>. we have to discharge the cap in max 9uS - length of h-sync + back porch | does not work: <strong>ATTENTION the 4053 can have up to 2k5 Ohms ON resistance</strong>. we have to discharge the cap in max 9uS - length of h-sync + back porch | ||
0.000009 = 0.22314355 * 2500 *C -> 16nF max | 0.000009 = 0.22314355 * 2500 *C -> 16nF max | ||
4n7/61k | 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. | 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 | discharge: 0.0005 = 0.22314355 * 2500 *C -> max 890nF | ||
charge: 0.003255 = 0.22314355 * R * 100nF, R = 145.8k | charge: 0.003255 = 0.22314355 * R * 100nF, R = 145.8k | ||
10k pot, 4k7 series and 10nF should do it |
Note: Spaces may be added to comparison text to allow better line wrapping.