fault IPS160H

[apenn.13]

hello,

I use the component in a board to control gas solenoid valves in a cooking plane.

I need to know for the regulations if in case of any fault or component breakage I always have a low or high impedance output value so as not to always excite the solenoid valve

That is to have a short between a VCC and OUT? or not?

[Domenico RAGONESE · Accepted solution]

Hallo @apenn.13​ 

Both events (hiZ or short) can occur to the integrated power switch between Vcc and Out pins of IPS160H.

You can detect such event on DIAG pin (activated when IN pin is driven low by the MCU) thanks to the "open load detection feature".

However, if you need to guarantee the HiZ in case of any fault (and consequently protect the load), then you need to introduce some redundancy.

I mean, you need another IPS160H (or a P-channel) in series to your IPS160H (you'll have primary switch and secondary switch; the latter connected to the load)

MCU has to check the diagnostic signals and switch off the primary switch in case of short on the power integrated in the secondary switch.

Hope it helps.

Best regards,

Domenico.

[apenn.13]

HI,

SO DO YOU CONFIRM THAT THERE MAY BE THE CASE THAT FOLLOWING THE BREAKAGE OF THE IPS160H THERE IS A SHORT BETWEEN VCC AND OUT EVEN IF THE IN IS LOW?

BYE

[Domenico RAGONESE]

Hallo @apenn.13​ ,

the short between Vcc and Out can occur both outside IPS160H (at application level) and inside the IPS160H (power switch in low impedance whatever the IN pin status is).

However, the DIAG pin can report the event independently if internal or external to IPS160H.

The IPS160H is really robust, but internal failure can occur from the violation of the AMR (e.g. Voltage or EAS violations...).

Hope it helps.

Best regards.

[apenn.13]

hello,

the spark to ignite the gas flame causes high voltage pulses both on the component inlet and on the solenoid valves out and sometimes they break when smoking.

Aren't they protected by esd?

the component is powered at 48V, just smbj48ca as tvs both on in and on Vcc?

better to put Ccutoff = 1nF?

Regards

[Domenico RAGONESE]

hallo @apenn.13​ ,

the IPS160H is protected against ESD.

However, depending on the ESD level of your application, it could be necessary to further protect the inputs by a resistor in series to the IN pin and by a capacitor between IN pin and ground.

It's not clear to me if:

• the damage in your module are on IPS160H or some other component.
• all the modules are damaged or only a subset

The SMJ48CA (Vclamp = 77.4V) could not enough to protect the internal clamp of the IPS160HF (AMR = 65V).

Could I suggest to see the behavior replaing it by SMJ40CA (Vclamp = 64.5V)? Drawback would be ~1mA leakage at 48V (due to lower Vbr).

About Ccutoff = 1nF: it may helps when the power switch is activated and an overcurrent event is activated.

If the problem comes from some overvoltage I don't think it can help.

Best regards,

Domenico Ragonese.

[apenn.13]

Thank you.

I have another question.

Can i put 5 V to Vin to activate Out with Vcc = 48V?

[Domenico RAGONESE]

yes, you can.

The input pin of IPS160HF is compatible with 3v3 and 5v0 logic levels.

(see table 7 in the datasheet).

[apenn.13]

HI,

I STILL HAVE PROBLEMS.

I HAVE MODIFIED THE CIRCUIT AS IN THE ATTACHMENT, BUT IN THE PRESENCE OF SPARKS THE COMPONENT BREAKS.

IN PARTICULAR IN CORRESPONDENCE OF PIN 7 EVEN IF THERE IS NO LOAD OUTPUT (OPEN)

WHAT SHOULD I DO AGAIN?

[Domenico RAGONESE]

@apenn.13​ .

We need to investigate even deeper:

1) can you send me a picture of the damaged IC?

2) Do you have the possibility to monitor the voltage between Vcc and GND (e.g. pins 1 and 7) during the spike?

3) Could you re-do the same acquisition, but with a short in paralle to R275 (and D24)?

4) Could you share the layout of your pcb?

I want to check the Vcc path and the position of the TVS D16.

Thank you in advance.

Best regards,

Domenico.