Pluto-P up/down Scheme and IR2110's

[epineh]

I am a little confused (as always ) about the PWM output from the Pluto-p and EMC using the up/down PWM scheme.

I had assumed it was a standard PWM signal on one pin and a NOT PWM signal on the other, but now I am wondering if it is more like a CW/PWM output on one pin and a CCW/PWM output on the other ?

My gate driver I am going to use is the IR2110. I am assuming that I need to put the "up" pin's output to the high input of one half bridge driver and the low input of the other half bridge, then the "down" pin to the opposite driver inputs.

Will that work as it is or do I need to add some logic to prevent a shoot through condition ?

Cheers.

Russell.

[samco]

the pluto-p can do Pwm-Up/Pwm-Down and Pwm+Dir. If you are doing something similar to my amp - simple 2 1/2 bridge drivers. You would use -Pwm-Up/Pwm-Down - which as you say is 1 pin that outputs pwm for spinning the servo clockwise and 1 pin outputs pwm to spin the servo counter-clockwise. You don't have to worry about shoot through - the Ir chips will take care of that for you. Plus - you would never have pwm coming out of both up/down pins at the same time.. Not that it would matter - it would just turn on both upper mosfets - acting as a brake. (same as no pwm in and both lower mosfets will be on acting as a brake)

Hope that makes sense...

sam

[epineh]

Hey Sam, thanks for the reply.

I don't believe that the 2110 has shoot through protection, in fact I figured that out on my first pluto-p attempt a couple of years ago, blew up the power stage, pluto, and PC (no opto's on the power stage ) It has hi and lo inputs for the same half bridge, so the circuit had one PWM going to the hi on one 2110 and the same PWM going to the lo on the second 2110...and vice versa for the other PWM.

I checked but found nothing that the 2110 will prevent shoot through from incorrect logic input, the 2184 line of chips will as they only have one logic input.

Once the smoke cleared I remember working out that the pluto was putting out PWM and direction, turned on both high and low sides of the same half bridge and ...smoke.

Cheers.

Russell.