User:Chotee/constantCurrentSink: Difference between revisions
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# RV5 (reference voltage adjust) to 5V. Test point at P3. | # RV5 (reference voltage adjust) to 5V. Test point at P3. | ||
# Set SW_A1 to non-EXT value | # Set SW_A1 to non-EXT value | ||
# RV1 (100mV voltage) to 100mV. | # RV1 (100mV voltage) to 100mV. Set SW2_B1 to bottom value, Set SW1_B1 to 1x gain (top pin). Use P1 as test point. | ||
# RV2 (10mV voltage) to 10mV. | # RV2 (10mV voltage) to 10mV. Set SW2_B1 next to bottom, Set SW1_B1 to 1x gain. Use P1 as test point. | ||
# RV3 (2x gain) to 100mV/10mV. Set SW1_B1 to 2x gain. Adjust until 200mV/20mV on P1 | |||
== Errata == | == Errata == | ||
* R5 @ 1k8: wrong value. Cannot get 2x gain with 1k8+5k pot. Change to 6k8+5k pot to get 2x gain. | |||
* R15 @ 10K: Doesn't give enough current to the LM336Z5.0. Switch to a lower resistance, 3k9 works for 9v input but. If 9v battery is used, voltage will droop till 7v during battery life. R15=1k5 will give stable reference 5V with a Vbat of 9V5 to 7V. Quiescent current does go up, but usable battery life will still be longer. | * R15 @ 10K: Doesn't give enough current to the LM336Z5.0. Switch to a lower resistance, 3k9 works for 9v input but. If 9v battery is used, voltage will droop till 7v during battery life. R15=1k5 will give stable reference 5V with a Vbat of 9V5 to 7V. Quiescent current does go up, but usable battery life will still be longer. | ||
Revision as of 23:02, 14 June 2015
Constant Current Sink
Goal: Will sink a constant current independent of the input voltage.
Range: 1mA to 5000mA. Max Vin 30V.
Ref 1 Build Notes
Adjustment
- RV5 (reference voltage adjust) to 5V. Test point at P3.
- Set SW_A1 to non-EXT value
- RV1 (100mV voltage) to 100mV. Set SW2_B1 to bottom value, Set SW1_B1 to 1x gain (top pin). Use P1 as test point.
- RV2 (10mV voltage) to 10mV. Set SW2_B1 next to bottom, Set SW1_B1 to 1x gain. Use P1 as test point.
- RV3 (2x gain) to 100mV/10mV. Set SW1_B1 to 2x gain. Adjust until 200mV/20mV on P1
Errata
- R5 @ 1k8: wrong value. Cannot get 2x gain with 1k8+5k pot. Change to 6k8+5k pot to get 2x gain.
- R15 @ 10K: Doesn't give enough current to the LM336Z5.0. Switch to a lower resistance, 3k9 works for 9v input but. If 9v battery is used, voltage will droop till 7v during battery life. R15=1k5 will give stable reference 5V with a Vbat of 9V5 to 7V. Quiescent current does go up, but usable battery life will still be longer.