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67 Threads found on Pwm Current Source
What is the best way to send pwm'ed audio from this circuit to a
hi, I want implement a constant current source with pwm control. 10mA is required at a load 1Kohm. The pwm should turn ON and OFF the load . The pwm frequency is 100Hz to 1KHZ with duty cycle of 10% to 80%. Regards
DAC is analog output. It also uses 1 pin. For 30Hz pwm also can be used. RC integration chain is needed and low pass filter in some cases.
Yes, question is a bit unclear. The ?A specification is about circuit quiescent current. Unclear is a least how the "pwm" dimming shall be configured. The usual solution is to use transistor switches (BJT or MOSFET) and current limiting resistors and generate the pwm inside the processor (least part count). If you (...)
In the LM5022 datasheet block diagram (page 8) there is a 1.4V voltage source, and a divider comprising a 100kohm resistor and a 50kohm resistor. (these are inbetween the error amplifier and the pwm comparator). Do you know what is the part to part tolerance on these values? LM5022 Datasheet
Hello, I have been tinkering with the constant current sources recently and want to drive my 30 W LED using it, I have simulated the circuit below and it seems to give me the correct current. Basically the current source (1A) is created using the OPAMP circuit, but I also want to pulse the output using (...)
pwm boost forward regulators are common with centre tapped transformer and differential drivers. But depends on current. For low current cascaded doublers can be used
Hello All, Can someone point me to a circuit, where I can pro-grammatically using SPI/I2C/pwm etc protocols set current source from 0mA to 500mA in steps of 1mA. may be an IC or even transistor-MOSFET based circuit design. Vin MAX= 24V Vin MIN = 3V Vout Max= 24V Iout= 0mA to 500mA in steps of 1mA .. (...)
I want to control single Phase AC 2-wire system's power (common household power) while keeping the terminal voltage intention is to utilize pwm output of my microcontroller to control the electrical energy supplied in a household. Please suggest some strategy or anyone already done this earlier. Thanks in advance.
Hi, I am simply trying to make a high current capable boost converter. I am giving input from an SMPS which can give a max 35A at 5V. I am making a digital variable boost converter which can give any voltage from 5 to 30V. I am using a 4.75mH torroidal inductor with around 10A DC current capacity but not sure about saturation current, (...)
Thanks, but supposing we are pwm dimming a 48V string of LEDs....then the current to the LEDs is going on and off, and the voltage across them has a ripple in it in phase with the pwm dimming, so in this case of pwm dimming, does the AC limit apply?, since there is an AC content to the LED current (...)
I am using pwm on AVR for audio generation. In order to control volume of speaker I want to use N-channel enhancement MOSFET and with the help of single switch I want to control volume as lowest --> lowish -->medium --> highish --> highest --> highish --> medium --> lowish --> lowest ... etc. And for different volume levels I want to use individual
Hello, Has anybody experienced problems when sending "pwm dimming style" current pulses down wires to LEDs (wires of length up to 2 metres long)?....I am referring to sending pwm dimming pulses to a 42V, 2.5A LED module. Presumably the current pulses should not have too steep sides or else radiated emissions will result?
Hi, The problem surely is not the mAh but more likely the voltage. Maybe the voltage drops and also maybe caused by pulsed current. For us it is not possible to find the error source, because your description gives only a few (unrelated) data. It sounds like "i have a car type XY, it works good when i drive to city1
If you consider a pwm driver like DRV10x , you can simply drive a transistor switch directly from MCU and get rid of the redundant D/A/D conversion. DRV10x or a direct processor controlled pwm don't provide constant current control, there should be a current feedback. I don't get the particular purpose of the (...)
Hi There I want build a weld inverter, but need it for mig only who needs a constant voltage supply. Now I have find a 3 - 60 volts supply with current adjustment (limit) from 0 to max 40 amps. It is the same topology a forward converter, I do use of the supply only the pwm chip uc3845 who is also in the current (...)
Hi I came across a H-Bridge FET Driver design where both high side outputs were set high (both high side inputs connect to the same microcontroller pin) when the motor was run in either side. The direction and speed was controlled by giving a pwm to low side input corresponding to the direction. Why would both high side outputs be set high togeth
hi all, i am designing a cpu fan controller using pic, i create a pwm pulse by using pic then connect directly pin4 (pwm) of fan, power supply of fan is 12Vdc, pin3 (tach) : not connect. the problem is the fan doesn't work match with pwm pulse, pls show me the problem. thx all
Specifications. 1 Amp continous current. Voltage range of 0 to Vdd Control signal type pwm(Microcontroller output) current sense to limit voltage output . Voltage is supplied from 2 lithium batteries connected in series to give 3.6+3.6v Dc.
Is there a way of making a node act as ground, without electrically connecting it to the ground. I have a pwm signal generated by a MCU. The signal is being generated with reference to the MCU ground. Now I have to drive a MOSFET using this signal, but it is not possible to join the MCU ground and the source-pin of the MOSFET together. Is there a