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2

Discrete MOSFETs already have a parasitic anti-parallel body diode. That's why they can only block current in one direction. Not ideal, but should suffice for just one last cycle during a blackout. Of course, you could also just add schottky diodes but not rely on them during regular operation and rely on synchronous rectification instead.


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You are on the right track. A bridge driver will solve many problems. You can use all N-MOSFET and do not have to worry about both transistors conducting at the same time. This one is great driver: Infineon ir2103 About Arduino the ATtiny402 can be used. Lot of information about fast PWM and code samples.


3

First of all, there is an error in your schematic. R4 needs to be connected between R3 and the base of Q1. Similarly for R8 on the other side. As shown, the circuit will not work — all of the transistors in the H bridge will be turned on simultaneously, shorting out your power supply. But even with this fix, you must never operate this circuit without the ...


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Answer (1) Q5 is to switch on/off Q1 or Q3, (2) R1 and R3 are to bias Q3, (3) R5, C2, D1 are to by pass noise (Note 1) and clamp input, (4) C1 is also used to by pass noise. Notes (1) A H-bridge with or without PWM usually operates at low frequency, so a bypass cap is usually used to filter high frequency noise caused by the DC motor. (2) You might like to ...


1

So the thing is that it is much easier to move electrons than to move holes. So a PNP has to be 3-10 "better" than a regular PNP to handle the current a NPN transistor can handle. That is the reason in the real world people prefer to use NPN transistors. Bottom line, You can have a PNP transistor that complement a NPN OR you can have 3-10 regular ...


2

In your H-bridge schematic, the same signal is being used to drive the bases for the upper and lower transistors. Because the top ones are PNP, and the bottom are NPN, the tops will conduct when the signal is low, and the bottoms will conduct when the signal is high. The L298 schematic shows that inputs for the lower pair are inverted. That's the little ...


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A 1Kohm resistor, against 5pF onchip ESD + Schmidtt noise_immunity circuit, would cause about 5 nanoseconds delay. If 5nS is well within the timing budget, then 1Kohm is a good value for surviving lots of external MISWIRE and ESD events.


9

Those old bipolar processes could only be used to make crummy lateral PNP transistors with quite low gain so not very good for high current. Using all NPN, especially those NPN, transistors is bad (because of the extra Vbe drop), but not as bad as it would be with monolithic PNPs. Popular? Probably for legacy applications and hobbyists, but I doubt any ...


1

Ref: http://www.orientalmotor.com/stepper-motors/technology/ You have a 6 lead motor designed for unipolar Nch switches, yet you are using a bipolar half-bridge IC. (BTS 7960 is not an H bridge.) Change drivers to a dual half-bridge with V+ on both centre taps or change the motor wiring to a 4 lead bipolar and H bridge driver for each coil.


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The schematic in figure 5 can be redrawn to look like this: - I've made a mirror image of figure 5 to show the transistors that make up the H-bridge. I've called them Q1 to Q4 to coincide with the transistor names in your final picture. So if the left-side output was pin 3, Q1 would be activated when pin 2 goes high. The right-side output is therefore pin 6 ...


2

If you have a great heatsink choose 1A otherwise consider an H bridge rated for 2A. Rohm is possibly the best source for H bridge motor drivers. From their catalog, I selected BD6212FP which is well-stocked at Digikey $2.38 (10) You still need a PCB and heatsink copper pour of 1sq" per W around each IC. I can't imagine a better choice for this ...


3

Is this a H-Bridge, why are the two ICs there Each IC is a half-bridge driver: - And, two half-bridge drivers control 4 MOSFETs in a full H-bridge Is it because you can't use the MOSFETs with as low voltage as 3.3V ? The MOSFET gates probably need significantly greater than 3.3 volts to turn on the device properly hence, the power rail for the chips is +...


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