eem2am
Banned
We are doing a LED Driver with ZXLD1360 Hysteretic Mode LED Driver.
ZXLD1360 LED Driver datasheet:-
**broken link removed**
The average LED current is being monitored with a microcontroller via a hi-side current monitor (ZXCT1081).
ZXCT1081 current monitor datasheet
**broken link removed**
Thus, the microcontroller can monitor the LED current, and gradually increase it over the years, so as to maintain brightness levels.
Since we have the current monitor, and we are reading its output with an ADC port on the microcontroller, we can be assured that we are setting exactly the required current at the required time.
The microcontroller is reading the current once every 500ms and , if necessary, correcting the LED current by applying a voltage to the ZXLD1360's "ADJ" pin.
The schematic is as follows:-
https://i46.tinypic.com/35m42zo.jpg
Considering the fact that hysteretic mode LED drivers are unconditionally stable,
-and also the fact that we are reading the LED current with the microcontroller every 500ms...
-and , if necessary , we are also applying a correction voltage to the ADJ pin of ZXLD1360 every 500ms.
....considering all this, what do you think the zero gain crossover frequency of the bode plot of the LED Driver would be?.........that is, the bode plots with respect to the LED current.......
.........would it be 2Hz or less?
ZXLD1360 LED Driver datasheet:-
**broken link removed**
The average LED current is being monitored with a microcontroller via a hi-side current monitor (ZXCT1081).
ZXCT1081 current monitor datasheet
**broken link removed**
Thus, the microcontroller can monitor the LED current, and gradually increase it over the years, so as to maintain brightness levels.
Since we have the current monitor, and we are reading its output with an ADC port on the microcontroller, we can be assured that we are setting exactly the required current at the required time.
The microcontroller is reading the current once every 500ms and , if necessary, correcting the LED current by applying a voltage to the ZXLD1360's "ADJ" pin.
The schematic is as follows:-
https://i46.tinypic.com/35m42zo.jpg
Considering the fact that hysteretic mode LED drivers are unconditionally stable,
-and also the fact that we are reading the LED current with the microcontroller every 500ms...
-and , if necessary , we are also applying a correction voltage to the ADJ pin of ZXLD1360 every 500ms.
....considering all this, what do you think the zero gain crossover frequency of the bode plot of the LED Driver would be?.........that is, the bode plots with respect to the LED current.......
.........would it be 2Hz or less?