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20 Threads found on Current Source Comparator
Hi, As in schematics, the output positive is directly connected, so if it get shorted to chassis or any ground of circuit, the sensing won't even know about it. Correct. But what happens: A short circuit will cause the fudīse to drop. And if it is able to sense it? What schould happen then. It is useless to switch OFF the MOSF
The loose tolerance on the above mentioned internal components means that the LM5022 will not be good for use in three 2500W boost converters which we need to be in parallel (Vin=200VDC, vout=400VDC). They will be in parallel with a single external error amplifier feeding back to all three LM5022?s. I am thinking the HV9910B will be better for
Hi guys, How can I measure the quiescent current in a comparator? Regards
Hi, you may also consider this circuit as a 'current comparator'. Esentially, the Vout vs Vin plot will be really similar to that of an inverter, but the triggering voltage will be shifted (determined by the sizes of the devices and the bias voltage of M2). Really, the output is High impedance and the exact voltage will be hard to be defined. For
I have this nagging feeling you are wasting your time with PWM drivers for this application when they will run nearly perfect on 48Vdc and just require 50mΩ current shunt, comparator & Mosfet. ..with ESR(FET) < ESR(LEDx1). if they are good LEDs. WHat specs for LEDs (V,I min/max ) and power source V,I min/max If Vf on 16 LEDs is (...)
Hey guys, the following circuit was attached to a boost convertor and is used to provide a 2 MHz frequency square waves to the Boost Convertor. My issue is when looking at the circuit, I realized I don't fundamentally understand how it achieves that. 1) So for example I understand that the second Op-amp is an integrator (since it has a capacitor i
You can put some back-up capacitors to increase the circuit working time out of external energy source. With the battery, supply a low power comparator (its current consumption actually depends of your need) with a battery supplied reference, say 3V, being the compared voltage one generated by the external power supply. The (...)
Referring to post #6, you'll find a gain calculation in the text book from where you copied the amplifier circuit (Razavi or whatsoever). The transistor Id and respective gm is primarly set by the current source transistor M5 and only slightly depending on Vcm, as long as all transistors are in saturation.
How triangular does it have to be? Perfect, or just "sort of ramp-y"? I've made ramp generators with switched RC, and ramps with switched or steered current source onto a capacitor. Both use limit comparators for the endpoints, banging a SRFF. The scheme gets flakier when your period approaches the order of (...)
The answer is in the circuit. If you don't see it, just try. When pulling the output voltage above regular Vcc-1.1V saturation level, you are working against a 50 ?A current source.
I agree to most explanation details, except for: Opamps can pull up or down (source or sink current). Many comparators sink current only. They rely on some external means to pull the output positive when the output is off. Only moderate speed comparators can have open collector/open drain without (...)
Changing XM1 and XM2 will alter the bias conditions and also reduce the gain from the differential input to the single ended output of the basic diffamp which is not desirable for any comparator. XM3 and XM4 act as the active current source load for the basic diffamp. And also, the current mirroring configuration of XM3 and (...)
Hi All, For an op-amp which will be used as open loop comparator, How do we simulate and judge the performance of the op-amp which include the following items: 1. Input voltage range 2. Output High voltage Vs Output Low Voltage 3. Output current source and sink capability 3 Input offset voltage 4. Frequency response ( Open Loop or (...)
Dear all, I need to design a 2 stage comparator that consumes low current. vdd = 1.4V and idd = 250nA, process is 0.25um cmos The comparator should work in a "slewing" condition. Can someone suggest a document or circuit for this ?? Thanks in advance.
Hello experts, I am working on a prototype board. I use LM7301 in comparator configuration. See the attached file. When current source I1 is switched off, I expected the V1 on non-inverting input voltage is not above 0.1V which I can accept. But the reality is V1 is about 3.5V!!! After all, the bias current spec in worst (...)
Can you propose some articles and expirience of current comparator design. I have to design AC and DC over current detector. current source wich have to be detected has DC and AC part. Each of these part has to be detected with relevant current comparators. Here I post (...)
Just use comparator. One input of comparator should be reference voltage, the other input has two~three bjt (serial)with current source. i.e., 2Vbe or 3Vbe should be another input. You can trim reference voltage with 2~3Vbe by simulation for trimming thermal shutdown voltage. Sorry to say 'I have no schematic'. (...)
i have a problem with my current steering dac (very high glitch) how can i solve it
isnt a diode connected transistor a better constant current source than a current course one,,since in the diode connected one Vgd =0 => the transistor is always in saturation ,but in current source transistor Vb given at the gate must be such that for all the output swings the transistor is in (...)
Try this circuit. The 1st opamp, transistor and resistor act as a current source and creates a ramp on the capacitor. The second opamp just acts as a comparator. The current is (Vcc-Vref)/R1. Time = C1*Vref/I = Vref*R1*C1/(Vcc-Vref) so you can set R1 and C1 to get time=1sec