sk540-ramps

You are viewing an old revision of this post, from December 10, 2013 @ 16:56:51. 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 1uF should do it

Module Info

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

Schematic & PCB

View on Github

Observations

No observations yet

Revisions:

Changes:

December 10, 2013 @ 16:56:51Current 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 -&gt; 16nF max 0.000009 = 0.22314355 * 2500 *C -&gt; 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 -&gt; max 890nF discharge: 0.0005 = 0.22314355 * 2500 *C -&gt; 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 1uF should do it  

Note: Spaces may be added to comparison text to allow better line wrapping.

Post a comment

You may use the following HTML:
<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>