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Smart Power Switches Forum Discussions

Not applicable
Hi!

I use Smart Highside Power Switch BTS6133D to switch the backup SLA battery. BTS6133D have Inversave (Inverse current capability) feature.

In charge mode current flows from VBB to OUT (normal flow). Charge current limited to 2A.
In discharge mode current flows from OUT to VBB (Inverse load current). Discharge current not exceed 7A.

If current direction change from normal to inverse with device is on (pin IN is low), no problem. Power switch remain ON and no excess power dissipation occur.
If the reverse current occurs when the device is switched off (pin IN is high), excessive power dissipation occurs when the current flows through the internal diode. This is understandable and normal.

I have problem and question:

With the reverse current occurs when the device is switched off (pin IN is high), external logic detects this mode and immediately set BTS61333D to ON state by set pin IN to low.
Unfortunately, with this BTS6133D remain OFF state and a high power dissipation continues.
It looks like it's not normal.
From reading the datasheet, it's unclear how 6133D should function in this case.

Best Regards,
Mikhail
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3 Replies
User13282
Level 3
25 replies posted 10 replies posted 5 replies posted
Level 3
Hello,

Here I have attached the Reversave section of the part.

Did you follow the advise that the overall current should be in the range of 80mA into the pin IN and IS? To provide this current a parallel diode is added to the bipolar transistor, you also can use a MOSFET or adjust the current by RIS.

2654.attach

Your problem is about the inversave mode.It should work as described here on the attached picture. Are you supplying power to VBB all the time?
2655.attach
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Not applicable
Hello berbra, thanks for your answer.

My very simplified shematic:
2658.attach

The problem described in the first message appears when the AC/DC converter is turned off and the battery is first time connect to the device.
In this case initially control logic is unpowered, AC/DC converter is switched off.
With battery first time connect to device, control logic powered by internal diode U2 BTS6133D. The control logic detects this mode and immediate switch the signal BATT_ON to a high logic level, transistor VT2 passes into a conducting state.
We expect that U2 should turn ON. But U2 remain OFF state. If VBB and OUT (U2) are short-circuited for a short time (with tweezers), then U2 switches to the ON state.
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Not applicable
Hello,

section 3.2.2 in Application Note "Inverse Operation Behavior of the BTS6143D and members of this product family" applied for BTS6133D? If yes, it is clear that the switch should not be switched on with inverse current.

2663.attach
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