Garloin27
Newbie
I am working on designing a current source for a LED driver, which can work up to max:16A, as long as the driver stays on less than 500msec. Actually, the leds circutry is a Dome-light which is divided in 4 sectors. The 4 sectors have a common ground and they are trigger in PNP mode(24Vdc) individually.
DOME light, 4 sectors
I am using a current sense-resistor of 10mOhm resistance, between a n-channel mosfet`s source terminal and ground. The voltage measured on the current sense-resistor is feed to a differencial OpAmp which output controls the mosfet´s gate voltage. Nothing new here, it is the simplest current source circuit. I am using a digital rheostat to create a voltage divider which sets the OpAmps reference voltage on the non-inverting terminal:
Components:
- TLV2372IP (Op Amp)
- MCP4162 (Digital Rheostat)
- STP55NF06L (Mosfet 60V,55A,Rds-On 18mOhm)
- Current sense-resistor 10mOhm/0.1% tolerance.
Basic schematic:
Questions:
*The circuit drives the current to the leds array with stability, but I know that this low-side driver will be unstabled if there is noise in the power supply or noisy enviroment like in a factory.It works steady only by chance. The power supply is a Meanwell DR-120-24/5A. Why can I get 4,6,8 or 15 Amps currents?If the power supply is rated 5 Amps max? (I didn´t have a higher current rated power supply at hand).
*I found in internet that a N-Channel or P-Channel MOSFET High-Side Drive should be more stable and worth to try. But How? I don´t know how to go about it. Could you give me some ideas, please?
This circuit it is for using the Dome_light for a photometric stereo machine vision application. Actually, I am a machine vision programmer. I am not an electronics engineer, sorry for not giving more information. Thanks in advanced
DOME light, 4 sectors
I am using a current sense-resistor of 10mOhm resistance, between a n-channel mosfet`s source terminal and ground. The voltage measured on the current sense-resistor is feed to a differencial OpAmp which output controls the mosfet´s gate voltage. Nothing new here, it is the simplest current source circuit. I am using a digital rheostat to create a voltage divider which sets the OpAmps reference voltage on the non-inverting terminal:
Components:
- TLV2372IP (Op Amp)
- MCP4162 (Digital Rheostat)
- STP55NF06L (Mosfet 60V,55A,Rds-On 18mOhm)
- Current sense-resistor 10mOhm/0.1% tolerance.
Basic schematic:
Questions:
*The circuit drives the current to the leds array with stability, but I know that this low-side driver will be unstabled if there is noise in the power supply or noisy enviroment like in a factory.It works steady only by chance. The power supply is a Meanwell DR-120-24/5A. Why can I get 4,6,8 or 15 Amps currents?If the power supply is rated 5 Amps max? (I didn´t have a higher current rated power supply at hand).
*I found in internet that a N-Channel or P-Channel MOSFET High-Side Drive should be more stable and worth to try. But How? I don´t know how to go about it. Could you give me some ideas, please?
This circuit it is for using the Dome_light for a photometric stereo machine vision application. Actually, I am a machine vision programmer. I am not an electronics engineer, sorry for not giving more information. Thanks in advanced