6
votes
Identifying unmarked IC in CNC controller board
On my board the marking is not completely deleted. With some effort I read STC 15F104W, it appears to be a little microcontroller.
Here is a link to a datasheet for the STC15F101 serie which include ...
- 61
6
votes
Dual-555 servo controller: how to "stabilize" without two separate voltage regulators?
But why?
Because your regulator circuit (including wiring/connections) isn’t stiff enough to remain stable with the load of a servo motor.
And it isn’t stiff enough because a LM317 needs at least 3V ...
6
votes
Accepted
Electric moped PWM MOSFETs failure
I think I can see enough from the photos to figure out what's happened. Mind, leaving it to others to puzzle things out is risky -- or likely to generate dubious answers or low activity -- clarity ...
- 43.3k
6
votes
Solenoid driver circuit with peak hold
advantage of the BJT could be to choose a base current so the BJT also could be used as a current limiter
It doesn't matter much if it would be a BJT or a MOSFET, since the control of the current has ...
6
votes
Solenoid driver circuit with peak hold
Below is the LTspice sim of a PWM Hit & Hold circuit for the solenoid:
It uses a CD4093 quad Schmitt-trigger NAND gate to generate a 10kHz PWM signal, which holds the solenoid at 10mA after the ...
- 429
5
votes
Accepted
Power switch for PWM not functioning as expected
Missed it on first glance, but I believe the problem is that you designed with the wrong footprint pinout numbers for the BTS 6143 D (U2). Your design was assuming the footprint pin numbers I marked ...
- 801
5
votes
Flyback Controller IC identification
The second one is probably an On-Bright OB3636A flyback controller. I found it by searching SOT23-6 "636" marking
The first one is more difficult. It's ...
- 6,706
4
votes
Why doesn't 5 V PWM (50% duty cycle) burn my 2.5 V rated LED?
The LED should burn out, but it seems your MCU or whatever chip that is outputing the PWM has so large source impedance that it can't burn the LED.
MCU IO pins and other IO pins from chips are rather ...
- 164k
4
votes
What parameter decides MOSFET switching response?
A MOSFET switching speed is mostly determine by how fast you can charge and discharge the gate charge, usually shown as Qg (total gate charge) on the data sheet).
Thus for fast switching you need a ...
- 429
3
votes
Accepted
MOSFET switching with PWM
\$
\def \ohm {\rm\,\Omega}
\def \farad {\rm\,F}
\def \sec {\rm\,s}
\def \usec {\rm\,\mu s}
\def \kHz {\rm\,kHz}
\def \volt {\rm\,V}
\def \amp {\rm\,A}
\def \watt {\rm\,W}
\$
What is the problem with ...
2
votes
Accepted
Help me to identify this IC marked '840M1D'
It's an On-Bright OB3840MP PWM controller.
I can't find a confirmed picture, but the marking style matches On-Bright and the pinout is plausible as well.
- 6,706
2
votes
Dual-555 servo controller: how to "stabilize" without two separate voltage regulators?
But why?
Hard to guess, we don't know how you power your motor, but that's probably critical here. My guess is that the motor draws enough current to make your regulators drop in voltage, and because ...
- 98.3k
1
vote
MOSFET switching with PWM
The following answers is not directly answering your question,but provide you with working alternative path best on my experience.
PMOS is not recommended to be used in high voltage circuit although ...
- 11
1
vote
MOSFET switching with PWM
What is the problem with the circuit I am making right now, I would be
very happy if you could help me.
When M1 activates, its drain falls to 0 volts and the full 126 volts appears between source and ...
- 467k
1
vote
Flyback Controller IC identification
The 631 may be an OB2263 (a PFC controller, as nanash suggests). There is more than one supplier with different markings, some of which resemble yours.
Your hand-drawn schematic appears to be ...
1
vote
Staggering PWM waveforms for servos to minimize current spikes
I hadn't looked at servo current use until very recently and was surprised by how spiky it is. The movement and current spikes are very synchronised with the control pulses. Here's an example of a ...
1
vote
Electric moped PWM MOSFETs failure
Your motor is running at 24V. According to the MOSFET datasheet, at that voltage the safe operating current of a single ...
- 667
1
vote
Amplifying current for PWM load
This simple BJT circuit will work in the low kHz range and can deliver up to 100 mA, however there is no overload protection.
At higher frequencies the values of R3 and R4 need to be lower.
The input ...
- 7,865
1
vote
Amplifying current for PWM load
You can use a two transistor buffer so the output is sink and also supplied with transitors (not sinking with resistor like your second schematic).
The Vcc should be the same or little higher than ...
- 2,300
1
vote
Use of series resistor on pwm output and serial communication
Series resistors are good for a number of things, depending on value.
In case of low resistance as in this case, the intention is most likely ESD protection. A series resistor isn't perfect ESD ...
- 21.6k
Only top scored, non community-wiki answers of a minimum length are eligible