Biasing of IR2110 Mosfet Driver

[Razor_Edge]

Hello,

I want to use IR2110 mosfet driver for a high power Class D bridge amplifier design i am starting. Could someone help me in biasing the IR2110 driver for single supply operation (bus Voltage is 50 volts) using IRF530 and IRF9530 pair?? An out of phase PWM signal is coming from a Schmitt trigger buffer 74HCT14 with a 5ns dead time delay between high side and low side from a 32 bit microcontroller. Thats all I have as information i have, as of now.

If someone can refer a link or thread for read and get to know other than IR's AN748 and IR798 (a & b) it will be wonderful because these two notes got me confused...


i will be really greatful...
thanks and regards

 

[Ouroboros]

The IR2110 is designed to drive a pair of N-channel FETs, so instead of your 530/9530 combination, you'll be able to use a pair of IRF530s.

There's a number of application notes on the International Rectifier site that show how the bootstrap power is arranged.

If you're only using a low voltage rail, you might be better off using the National Semiconductor LM5104 (or another part in the LM510x range) instead.

 

[Razor_Edge]

The IR2110 is designed to drive a pair of N-channel FETs, so instead of your 530/9530 combination, you'll be able to use a pair of IRF530s.

There's a number of application notes on the International Rectifier site that show how the bootstrap power is arranged.

If you're only using a low voltage rail, you might be better off using the National Semiconductor LM5104 (or another part in the LM510x range) instead.

thanks Ouroboros... 🙂

Since the design uses a intelligent device, I might be as well give a try to go beyond 100 volts bus voltage. I suppose IR2110 will be the right choice for this design. Moreover, since i will be commercializing this design i have to rely on the locally available components. IR2110 is less than 50 cents here (best in class i would say)...

I have gone through many application notes from IR on using 2110... confusion is about using 4 of N channel mosfets in H bridge for single supply operation. I just can figure out how the whole thing will work on balanced current architecture...

could you possibly guide me??

thanks again for all the help

 

[sivan_and]

Ouroboros !!
Razor_Edge is using the p,n channel mosfets as buffer to output mosfets ...U need to use a buck convertor first to convert 50v to 15volts..
IR2110 is normally used on 15volts rail...for Mosfets -ve supply is not required..but for IGBT's is a must for better turn off!!
Bootstrap power (for driving high side mosfets)is obtained by using a fast recovery diode+capacitor combination.
Pls do serch forum for more details..

 

[Ouroboros]

Aah sorry! I should have read the original a bit more closely and realised it was for a high power design.

If the design requires an external power buffer between the IR2110 outputs and the power FETs then there's obviously no problem in powering the buffer to drive the lower FET, but the floating 12/15V supply driving the upper FET will need to be able to source more current than would be required if you were driving the output gate direct from the IR2110. Perhaps a seperate floating 15V supply from a dedicated mains tranformer might be the easiest solution?

If you do use a seperate 15V supply fed from its own mains transformer, you should add a common-mode choke between the output of the supply and the power-amp. The top FET gate drive is swinging between the power rails at the switching frequency of the class-D amp and the C-M choke will prevent this large common-mode swing from causing a lot of ac current flowing to earth via the capacitance to ground of the floating supply.

 

[Razor_Edge]

If you do use a seperate 15V supply fed from its own mains transformer, you should add a common-mode choke between the output of the supply and the power-amp. The top FET gate drive is swinging between the power rails at the switching frequency of the class-D amp and the C-M choke will prevent this large common-mode swing from causing a lot of ac current flowing to earth via the capacitance to ground of the floating supply.

Thanks for a prompt reply.

well, I am using an syncronous smps generating 12 volts for the signal conditioning and pre amp section as power supply. thanks for the common mode choke thing, u r right, I am driving the output fets directly fron the HVIC.. But I still need something to start with. can you tell me how the bootstrp cap and which diodes to you for fast charge ups?? this IC suffers from bad glitched power supplies, erratic behaviour at turn on.

If i can get a circuit diagram or any applicaition note having a schematics using ir2110, it will be splendid..

 

[Razor_Edge]

Charles please help me...??

Hello Charles,

I dont know how to bias/use IR2110 for single supply H bridge operation. Could you please help or guide me. I have already tried through enough app notes. Got completely confused now....

Please help

 

[phase_accurate]

One thing has already been mentioned: The ICs have to be fed with around 15 volts. The high-side driver is fed via a bootstrap capacitor. It is important that both ICs have their own bootstrap circuit. To say it in other words: A bridge application is the same as two standalone single-ended driver/output stages.
The spaciality is just that their inputs are driven with different phase and the load is connected accross both outputs.

Best is you make a sketch of what you intend to do and we will be able to correct it.

Regards

Charles


BTW: What do you mean by BIAS ?

 

[sivan_and]

Ir2110

Hope this will clear everything ?

 

[Razor_Edge]

Best is you make a sketch of what you intend to do and we will be able to correct it.

Regards

Charles


BTW: What do you mean by BIAS ?

By BIAS i meant how should I connect the power to the MGD for correct /required operation. I hope, i didnt use this word at a wrong place.

Please find attached is the circuit diagram for your reference.

IN+ and IN- signals are taken from a balanced current modulator. Triangular wave is generated by integrating a square wave from a 555 timer configured for 400Khz frequency for full range front channels.

though a costly option, I wanted to use N and P channel Mosfets for simple design. I am open to experienced recommendation on using N channels for high side using a 7404/7414 to invert the signal.

I am also not quite sure about the compatibilty of the IR2110 for TTL level signals. Please advice.


since this is a stackable design (output stages can be paralleled to the PWM signal) I plan to keep it the DSP section and mother board seperate from the output stage. using shielded cable the IN+ and IN- signals will drive the secondary output boards.

I hope, I have conveyed the whole picture.

Please comment....

 

[Razor_Edge]

Re: Ir2110

Hope this will clear everything ?

Thanks for the info sivan. but, I have been told that this convetional scheme distorts the output waveform if the bus voltage on the Mosfet is more than 60 volts. have you ever encountered such erratic behaviour in this MGD??

had kept my fingers crossed (just incase)...🙁

 

[phase_accurate]

Using two N-channel devices is still cheaper because of the superiority/availability of these devices compared to P-channel despite the need of an additional inverting stage.

Furthermore you don't use any means to introduce dead-time (in order to reduce shoot-through) in your circuit. Use a resistor with a parallel diode between gate and driver output in order to cause "slow" turn- on and fast turn-off. The 2110 has some intrinsic deadtime but this doesn't work at all with a complementary stage.

The logic levels of the inputs are depending on the supply voltage of the input logic (VDD). The lower the supply-voltage the lower the levels. But even when supplied with 5 volts I wouldn't recomment TTL levels as input signal. Use CMOS levels for proper and safe switching.

Regards

Charles

 

[Razor_Edge]

Using two N-channel devices is still cheaper because of the superiority/availability of these devices compared to P-channel despite the need of an additional inverting stage.

Furthermore you don't use any means to introduce dead-time (in order to reduce shoot-through) in your circuit. Use a resistor with a parallel diode between gate and driver output in order to cause "slow" turn- on and fast turn-off. The 2110 has some intrinsic deadtime but this doesn't work at all with a complementary stage.

The logic levels of the inputs are depending on the supply voltage of the input logic (VDD). The lower the supply-voltage the lower the levels. But even when supplied with 5 volts I wouldn't recomment TTL levels as input signal. Use CMOS levels for proper and safe switching.

Regards

Charles

thanks Charles, you have been a great guide. well I will now use N channel for high side too...!! 🙂

Ya, i need to introduce dead time in the gate drive section. would you recommend PNP based turn off. thats because I dont want to go for more than 25 nsec dead time (4.7 ohms resistor). THD figures is what i am a bit worried about at such high powers(7 to 8 amps @ 50 volts)...

For input, shall i use 7407 or similar... or should I use CD4069 hex inverter?

thank you once again.

 

[phase_accurate]

First of all: Even though this might be intended for subwoofer use you'd better let a mod move this thread to class-d since you will attarct more attention there.

This driver IC is sufficiently capable of driving an IRF530 so I don't think an active discharge circuit will have much advantage.

For the inversion of input signals it is advisible to use a circuit that shows the same delay for both input signals.

Therefore a circuit is usually used with two gates of the same kind (one before each input of 2110). So the best solution is CMOS XORs with one input of both driven by the PWM signal and the other input connected to L for the non-inverting stage and the 2nd input to H for the inverting stage.

Regards

Charles

 

[Razor_Edge]

First of all: Even though this might be intended for subwoofer use you'd better let a mod move this thread to class-d since you will attarct more attention there.

U have a very valid point. How should I contact a moderator?? Thanks for the information any way. I didnt knew it is possible.


I wanted to work on with active discharge on the gate, because I will put three mosfets in parallel to get higher current capability once the whole system is up and running. what do you say?

I work for a distributer comapny as a FAE and we represent APT too. So i wnated to lay my hands on APT IGBTS (T0263 package) for only the subwoofer amp section. would this circuit required too much of modification apart from the slow rise and fall times??

thanks again...

 

[phase_accurate]

There is a little button down on the righthand side you can use this to report a thread/post to a moderator. It is named "report".

If you want to use many FETS with high gate-charge in parallel you might not get along without active discharge circuitry, and maybe not even without a buffer for charging if you are going to the extremes.

OTOH 3 pieces of IRF530 have gate-charge in the same ballbark as one IRF 640 which have often been used with the 2110.

I wouldn't recommend the use of IGBTs for switching amps.

Regards

Charles

 

[Razor_Edge]

OTOH 3 pieces of IRF530 have gate-charge in the same ballbark as one IRF 640 which have often been used with the 2110.

I wouldn't recommend the use of IGBTs for switching amps.

Regards

Charles

🙄

thanks again charles...

How would i be able to extract 1000 watts out of a switching amp running on a bus voltage of 70 volts?? which common and reliable mosfets would you recommend for 70 volts full bridge amp delivering 1000 watts RMS. 😕

One more question Why do you disagree using IGBT's for switching amps?? I thought they are way too powerful at low frequencies then their mosfet counter part... Please elaborate.