Example of using Mofset driver

Hi everyone.Here is a a circuit showing how a "PWM Solar Charge controler" works. the principal work of this controler is using arduino's PWM to switch on the transistor 2N3904 to let the 12V battery absorb the energy from the solar pannel when the voltage of the solar pannel is under the actual battery's voltage and in an opposite situation the transistor should be switched off. so using the mosfet driver (wich is in the middle of red circle) is an important thing but i still dont know how it works ?!
after many researches i found that the driver is there to provide the current and also drives the gate with an appropriate voltage level not high to avoid the risk of damaging the mosfet but also high enough to produce a low Rdson. But my question is how it works ?!! when the transistor 2N3904 is switched on where the curent goes ? why do we need the mosfet IRF95530 ? to amplify the voltage ? but how the current get into the mosfet ? can anybody tell me how the Mofset driver work ?!!

Hi,

One key value for correct operation is the voltage.
--> tell us the valid range of C1 voltage.
******

The Moseft Q1 acts as a switch.
* It is OFF when Vgs is below a certain threshold (simplified)
* It is ON when Vgs is above a certain threshold (simplified)
* the gate needs about no current.

Bjt T1:
* The bjt controls Vgs of the Mosfet Q1
* it amplifies the PWM signal
* and it modifies the reference point somehow. The signal PWM is referenced to GND .... after the bjt the signal is referenced to V+ which is equal to mosfet_source.

Klaus

thank you for answering me mr klausst. the Capacitor C1 is used to remove any unwanted noise/spikes.

i still dont understand how the driver mosfet works especialy when its about knowing how the final curent go into the battery i know "WHEN" but not "HOW" begining from the transistor to the mosfet

Hi,

1) answer my questoin about the valid voltage range
2) go step by step from "PWM" input --> R4 --> T1 --> R3 --> Q1 --> battery
Then tell us step by step what you know. Voltage, current, behaviour..
Then tell us what is not clear.

--> ask dedicated questions, not global

Klaus