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I would like to know if this is a H-Bridge: enter image description here

Why is there IC3 and IC4? Is it because you can't use the MOSFETs with as low voltage as 3.3V? This motor is probably driven with a STM32 and PWM. I have a general understanding of PWM, but why do I need to give the IC3 and IC4 a inverted signal of my PWM flank? Can't the IC just assume, if there is no high on the HI pin, there is a high signal on LI? Can you tell me something of the overall "quality" of this circuit?

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  • \$\begingroup\$ Can't the IC just assume, if there is no high on the HI pin, there is a high signal on LI ? Sometimes you might want to simply disconnect the motor from HI as well as LOW and let it run freely. \$\endgroup\$ – AJN Jul 13 at 9:57
  • \$\begingroup\$ Is this the IC ? ti.com/lit/ds/symlink/lm5102.pdf?ts=1594634135070 \$\endgroup\$ – AJN Jul 13 at 9:58
  • \$\begingroup\$ Yes it is an H-bridge, using two half-bridge drivers. Where did you get this circuit from? \$\endgroup\$ – Bruce Abbott Jul 13 at 10:03
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Is this a H-Bridge, why are the two ICs there

Each IC is a half-bridge driver: -

enter image description here

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 +10 volts. In fact, page 4 (figure 3) tells you that you should really be using in excess of 6 volts of gate voltage to drive the IRFH7085PbF properly. This is to avoid thermal runaway and device failure.

Can't the IC just assume, if there is no high on the HI pin, there is a high signal on LI ?

No you can't; the two chips have to be connected with inverted input signals as per the red and blue boxes in the picture below: -

enter image description here

Can you tell me something of the overall "quality" of this circuit ?

Well, the motor is not stated so we can't tell what sort of load current it will pull so this stops us in our tracks from any reasonable analysis. Neither are there details of the power supply so this doesn't help either.

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    \$\begingroup\$ Very informative, well the motor says "PT-775PM-8013 18VDC P181224 No. ZKT01353" I am sure this means something. And the battery says "5INR19/65 Lithium-Ion 18V 27Wh 1.5Ah", something you would find on a cordless screwdriver. I just posted this to complete the information, but your answer already helped me alot. \$\endgroup\$ – Stackoverflowsuperbad Jul 13 at 11:45

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