2_Channel Half Bridge Gate Driver Charge Pump

[Alberto Dan]

Hy,cand someoane explain me what is the role of transistor Q1 and how that circuits work?I try to understand but i can't.Voltage VS is the power supply of a Internal Charge pump of IC.
Out "CP"is out Charge pump who is a Periodic waveform.From datasheet if VBAT is grater than 13.5V then "Vcp" is "VS+11V".If VBAT is grater than 22V then Charge pump is close and "Vcp=0V".
Now i cand understand what is happened there,and what is the role of Q1 transistor,because is a N tipe and the base is connected at the GND throught that resistor,so basicaly don t do anithing,is in BLOCK state.
The Vcp voltage feet the Grill of NFET transistor.From my opinion i understand that,if Vcp is HY than VP=VBAT,and if Vcp is low VP=0V.

I don t understand here what is the role of charge pump,who influences the gate of exernal MOSFET driver,and what is the role of there TBJ,and zenner diode.

Can somebody explain me please??

See atachament for picture!

 

[FvM]

Haha, unfortunately this detail of the application circuit (around Q1 and MOSFET) seems to be not mentioned at all in the Rohm datasheet.

It's not directly related to charge pump operation, rather it's using presence of the charge pump voltage (Vp > Vbat) to enable the switch supplying the output transistors. Q1 implements a supply reversal protection function.

Purpose of the charge pump as such is verbosely explained in the datasheet, don't think it's appropriate to retell the respective paragraph.