Best way to reduce VGS voltage in this driver

Thread Starter

Dever

Joined May 2, 2022
21
Hi,
due to simplicity, I build the driver for H-bridge, which is powered by 24V. However, I find it difficult to get N-MOSFET on stock with VGS > 20V. I was even thinking about get rid of my driver and use IRL540 and IRF4905 (hope +5V will chocke them up).

My idea is to put resistor on collector and down to emitter of Q1. Other way is to find proper and popular IC on Vsupply >24V and Vout <20V.
1657139909965.png
 

ronsimpson

Joined Oct 7, 2019
2,174
IRS2004 With this IC you can use all N-mosfets. It makes certain that one fet is off before the other one is turned on!
It needs a supply Vcc voltage of 10 to 20V.
1657161423673.png
 

crutschow

Joined Mar 14, 2008
30,150
Your P-MOSFETs need to be upside-down (source should be connected to +24V).

To reduce the gate voltage to 12V, you can increase the series resistors to 500 ohms and add a 500 ohm resistor from each MOSFET's gate to source.
 

Thread Starter

Dever

Joined May 2, 2022
21
Pardon for small mistakes on picture. Thanks for answers. Then, I will try increasing the series resistors to 500 ohms and add a 500 ohm resistor from each MOSFET's gate to source. Switiching frequency is less than 10kHz.
 
Last edited:

Ian0

Joined Aug 7, 2020
5,576
Hi,
due to simplicity, I build the driver for H-bridge, which is powered by 24V. However, I find it difficult to get N-MOSFET on stock with VGS > 20V. I was even thinking about get rid of my driver and use IRL540 and IRF4905 (hope +5V will chocke them up).

My idea is to put resistor on collector and down to emitter of Q1. Other way is to find proper and popular IC on Vsupply >24V and Vout <20V.
View attachment 270883
I would recommend a half-bridge driver such as MIC4102, FAN73932 etc. and four N-channel devices.
MOSFETs with Vgs>20V of any polarity are very rare, and driving any MOSFET with more gate voltage than necessary is probably not such a good idea.

If you want to continue with the N-channel/P-channel half bridge, put another 1k resistor in series with R4, then connect Q1/Q3 bases to the junction of the two resistors. That will limit the gate voltage on the P-channel devices to 12V. (as per @crutschow , post #5)
 

Thread Starter

Dever

Joined May 2, 2022
21
What about using 7815CV as voltage supply for my driver or MIC4102? So, MOSFETS are powered by 24V and MIC4102 via 15V from LDO.
 
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