Active Elevated Rail Hi side Bootstrapping Technique for IR2110

Workhorse · 10th April 2007, 01:24 PM

Hi Folks,

I have successfully implemented this elevated rail bootstraping technique to prevent failure mode in IR2110 gate driver during low frequency heavy clipping conditions...

Your comments please....

Kanwar

phase_accurate · 10th April 2007, 01:35 PM

R U sure you have drawn it right ?

One possible solution can be found on IR's website (some charge pump using a 555).

Another one would be the use of a simple current-source from your elevated rail. You wouldn't need much current supplied by this (in the range of 350 uA IIRC).

Regards

Charles

BWRX · 10th April 2007, 01:41 PM

Can't you just use the positive rail, an emitter follower, and a larger capacitance?

Workhorse · 10th April 2007, 01:41 PM

Mine isnot a current source, its a voltage source type of 15V floating and is referenced to the source....I have tested the amp with DC at input also and the output easily delivers it without any damage in continuous load....

Workhorse · 10th April 2007, 01:45 PM

Quote:

Originally posted by BWRX
Can't you just use the positive rail instead of the "elevated" rail?

When you want to drive low frequency signals, the charge in bootstrap caps decays and the Mosfet enters linear conduction mode and would get damage,but using this elevated rail of VCC+15V the cap always remains charged, even if DC signal is used at the input of amp[provided DC coupling]...

BWRX · 10th April 2007, 01:47 PM

Quote:

Originally posted by Workhorse
using this elevated rail of VCC+15V the cap always remains charged

I realized that after I posted, and edited my previous post

Your scheme makes sense but if you don't plan on amplifying DC wouldn't it be easier to just increase the value of the bootstrap cap?

Workhorse · 10th April 2007, 01:49 PM

With this technique the amp can act as continuous DC voltage source....

phase_accurate · 10th April 2007, 01:51 PM

The base voltage must be higher than the emitter voltage to turn on the transistor. So I think you have drawn the circuit differently than you actually implemented.

Quote:

Can't you just use the positive rail, an emitter follower, and a larger capacitance?

This wouldn't help since it wouldn't allow sustained turn-on of the upper MOSFET which is what is intended here. The idea is to allow driving the amp heavily into clipping without causing latchup or worse.
Not that heavy clipping should be a usual mode of operation of any amp - but it is always good practice to design things such that they survive any type of misuse.

Regards

Charles

Workhorse · 10th April 2007, 01:51 PM

0-100% duty cycle could be realized,no smoking of amp during continuous clipping of low frequency signals at output....

Workhorse · 10th April 2007, 01:55 PM

Quote:

Originally posted by phase_accurate
The base voltage must be higher than the emitter voltage to turn on the transistor. So I think you have drawn the circuit differently than you actually implemented.

Regards

Charles

Yes,
Actually
The elevated Rail voltage is 25V
The Zener voltage is 16V and thus the floating bootstrapping voltage is around 15V[including losses]....perfect to drive the mosfet during heavy clipping

10th April 2007, 01:41 PM	#3
BWRX diyAudio Moderator Emeritus Join Date: Jan 2005 Location: Pennsylvania	Can't you just use the positive rail, an emitter follower, and a larger capacitance? __________________ Brian

10th April 2007, 01:41 PM	#4
Workhorse diyAudio Member Join Date: Dec 2004	Mine isnot a current source, its a voltage source type of 15V floating and is referenced to the source....I have tested the amp with DC at input also and the output easily delivers it without any damage in continuous load.... __________________ It's a fruitless endeavor to try and educate a fool that rejoices in ignorance

10th April 2007, 01:49 PM	#7
Workhorse diyAudio Member Join Date: Dec 2004	With this technique the amp can act as continuous DC voltage source.... __________________ It's a fruitless endeavor to try and educate a fool that rejoices in ignorance

10th April 2007, 01:51 PM	#9
Workhorse diyAudio Member Join Date: Dec 2004	0-100% duty cycle could be realized,no smoking of amp during continuous clipping of low frequency signals at output.... __________________ It's a fruitless endeavor to try and educate a fool that rejoices in ignorance

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

10th April 2007, 01:35 PM	#2
phase_accurate diyAudio Member Join Date: May 2002 Location: Switzerland	R U sure you have drawn it right ? One possible solution can be found on IR's website (some charge pump using a 555). Another one would be the use of a simple current-source from your elevated rail. You wouldn't need much current supplied by this (in the range of 350 uA IIRC). Regards Charles

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Single rail, active I/V for TDA1543, TDA1545A	rbroer	Digital Line Level	69	26th August 2009 11:25 AM
ac side active PFC	basreflex	Power Supplies	1	7th January 2009 06:58 PM
how ir2110 drives the high side mosfet in h bridge	gowri	Class D	2	10th April 2008 06:30 AM
DC heater (+/-) -> elevated?	Cobra2	Tubes / Valves	3	29th March 2008 02:39 PM
ir2110 and 6 x irf640 per side?	jake83	Class D	8	4th March 2007 01:08 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read