Other Parts Discussed in Thread: INA237, INA238, INA228, LM5066I, LM5069, TPS2490, LM5060
I am currently using a high-side MOSFET driver and an INA237 to manage a 60V, 40A bidirectional switch (100% duty cycle), but I now need to add bidirectional hot-short protection.
The INA237 alert fault is too slow to keep the MOSFET within the SOA (need under 10us detection) and the existing gate driver does not have fast enough off-time. MOSFETs are IAUT300N10S5N015 with a gate charge of 216 nC each.
Enable is controlled by a microprocessor that also handles the minimum start-up which is 42V. Load can be capacitive, so a pre-charge circuit for dv/dt control is required, but can be a separate circuit.
Accuracy of the current and voltage sensing is important for energy measurements and should be as accurate as possible, so in most cases the INA237 (or upgrade to INA238 or INA228) will stay.
Requirements:
- 60VDC operating voltage
- < 10us short-circuit protection (bidirectional)
- common source bidirectional switch support
- Bidirectional current monitor output if replacing the INA237
I am having trouble finding a suitable solution that supports bidirectional current measurement. Are there any options that I am missing in the list below?
TPS48111-Q1
Short circuit protection is 1.2us. Has precharge circuit which is a bonus. Bidirectional switch is supported. Current monitor output is not bidirectional and if the block diagram is accurate, the short circuit protection is not bidirectional, so I would need to put two of them in series and based upon the internal block diagram, it looks like I would need a shunt resistor for each. I would keep the INA237 in this case and hopefully use one of the driver current shunts instead of adding a third shunt.
LM5066I
Has Vds and Id measurement to stay within SOA for short circuit protection. Has dv/dt control for starting capacitive loads, so may not need the pre-charge circuit. Current measurement is not bidirectional, so I would need to put two in series and use a shunt resistor each. I would keep the INA237 in this case and hopefully use one of the driver current shunts instead of adding a third shunt.
LM5069
Has Vds and Id measurement to stay within SOA for short circuit protection. Has dv/dt control (extra circuit) for starting capacitive loads, so may not need the pre-charge circuit. Current measurement is not bidirectional, so I would need to put two in series and use a shunt resistor each. I would keep the INA237 in this case and hopefully use one of the driver current shunts instead of adding a third shunt.
TPS2490
Appears to be the same as the LM5069 from a functionality standpoint.
LM5060
Nice chip that doesn't require a shunt resistor, but is not recommended for short-circuit operation.
Looking forward to some ideas I have not yet considered.
