CD4013B: High current dissipation around 500uA-2mA, Vcc 6.5v

LeoChen

Part Number: CD4013B

Dears,

End customer's application is designed for gas meter. Issues happened, high current dissipation from CD4013B.

We found if we cut off end circuit, current still dissipation around 500uA-2mA from CD4013B.

Normally, Q15 is open, when load circuit short, R58's voltage will work more than 0.6v, this will drive Q15 work, and Pin6 Set a under high level voltage, then Qa pin will output high level voltage, it will drive Q13,Q14 work on opening status. it will cut off load circuit.

Questions: What condition will produce high current dissipation from CD4013B

over 5 years ago

0 Emrys Maier over 5 years ago

TI__Guru* 96712 points

Hi Leo,

Can you provide a scope shot showing these pins when the excessive current is detected:

1, 3, 6

My initial guess would be that the slow inputs from the large RC values on some inputs is causing excessive current as described here:

https://e2e.ti.com/support/logic/f/151/t/737694

0 LeoChen over 5 years ago in reply to Emrys Maier

Intellectual 500 points

Dear Emrys Maier,

Before testing, we remove Q14.

Then test pin 1,3,6's current, and found 1,3,6 current is 0.

But Vcc pin's current is always around 500uA.

PIN1

PIN3

PIN6

0 Emrys Maier over 5 years ago in reply to LeoChen

TI__Guru* 96712 points

My apologies for not being more specific. I need to see the voltage waveforms at the time when the current is excessive.

0 LeoChen over 5 years ago in reply to Emrys Maier

Intellectual 500 points

Dear Emrys,

We test again to add voltage waveform figure.

Turn on to this circuit, Current total dissipation change to 750uA then to 650uA, finally keep on 700uA dissipation. Vcc is 6.5v.

Vcc 6.5v, PIN10V, PIN3 6.42V, PIN6 0V

PIN1 Current 0.14uA, Voltage is 0v.

PIN3 Current 0.6uA, Voltage is still 6.42v

PIN6 Current 0uA, 0v voltage.

0 Emrys Maier over 5 years ago in reply to LeoChen

TI__Guru* 96712 points

Hey Leo,

Sorry for the trouble, but I can't see any of the images you posted. Sometimes E2E can be troublesome if you try to copy/paste images. Typically the best way is to use the "Insert/Edit Media" button in the posting toolbar. You can also zip up the images and attach them as a single file.