We want to use ADuM4223 in the full bridge driver application. Do you have the reference circuit for this application?
The ADuM4223 can be thought of a 2 separate isolated gate drivers within one package. This allows many different configurations for a full-bridge setup. The easiest setup, if you can guarantee a minimum switching frequency and suitable duty-cycle to support a bootstrap configuration looks like two ADuM4223's, one on each leg of the full-bridge:
In this configuration, Q1 and Q4 are typically fed the same signal, and Q2 and Q3 are in sync. Vaux in this example is an isolated supply, but if primary to secondary isolation is not required, Vaux could share a ground with Vprim.
If you need to have any of the MOSFETs pm for an indefinite amount of time, this configuration will work, but will cost you two extra isolated power supplies. VHI_R, and VHI_L MUST be isolated power supplies in this case, as the ground reference for the high-side drivers must follow the half-bridge midpoint voltages.
Lastly, if you need another reference for implementation, the application note Circuit Note | CN0196 | H-Bridge Driver Circuit Using Isolated Half-Bridge Drivers | Analog Devices uses an ADuM7234, but two ADuM4223's can be used instead. Using an ADuM4223 in place of the ADuM7234 will yield higher creepage distances and stronger gate driver strength, and is the recommended part for most full-bridge applications.
Thanks for your data.
And how to choose the bootstrap diode in the bootstrap circuit if the Vbus is 400V?
The bootstrap capacitor size is independent of the bus voltage. It depends on the switching frequency, duty-cycle, and quiescent current of the high-side driver. The circuit note http://www.analog.com/static/imported-files/circuit_notes/CN0196.pdf covers sizing the bootstrap capacitor.
Without know the minimum switching frequency and duty cycle of a particular design, I can't suggest a bootstrap capacitance. I suggest looking at the bootstrap capacitor sections in the circuit note first.
There are still two questions need your helps.
1. Below is the full bridge circuit, sometiome, the MOSFET will be failed. Please kindly check the circuit is OK or not.
2. The booststrap diode will failed in the below application(Vbus is 400V), what is the max diode voltage?
1. There is a small mistake in the circuit, but it is probably just in the drawing, not the actual circuit:
This circuit looks good, if 112V_P, 2V_Q1, and 12V_Q3 are isolated power supplies. How often does the MOSFET fail, and which MOSFET is it?
2. The bootstrap diode will see the bus voltage + 12V + overshoot across it. For a 400V bus, I would guess a 500V rate diode should be good. A common choice for bootstrap diodes is the MUR series, such as the MUR150.
Another cause of the bootstrap capacitor failing could be from overcurrent. If the highside MOSFET fails and causes damage to the A channel of a driver, a short could be formed between VDDA and GNDA. Once that happens, if the lowside channel brings the midpoint voltage to GNDB, the bootstrap diode would see high current and fail.
The cause of the MOSFET failing could be many things. Here are a few:
1. Temperature overstress
2. Repeated peak voltage stress due to ringing
3. Timing error on input side of gate driver
4. Saturation of a load inductor
5. Short circuit on load being driven
Is there any noise on VIA and VIB? Sometimes with a resistor divider network VIA and VIB can be more susceptible to noise from high currents. This is because with a resistor there, a high impedance is seen from the input nodes.
Thanks. Will check it.