bq500212a snooze and sleep problem

chankyu kim

Prodigy 40 points

Other Parts Discussed in Thread: BQ500212A, BQ51013B

Hi~

I have a questions regarding the bq500212a snooze and sleep functions

My sample board with bq500212a is not work correctly about snooze and sleep function.

When bq500212a power up without Rx(bq51013b), it is not enter snooze mode, so Input current is about 50mA

When with Rx, bq500212a is OK

attach my schemetic

thanks in advanced.

0456.FIT-WPT120M_WS10_140603.pdf

over 11 years ago

0 Bill Johns over 11 years ago

TI__Guru* 75866 points

What value of resistor are you using for LED_MODE (Pin 44)?

I recommend 42.2k for LED Mode 1.

If 48.7k is use the LED Mode is 2, this is an mode where the unit and LEDs are on in standby.

0 chankyu kim over 11 years ago in reply to Bill Johns

Prodigy 40 points

I am using 48.7k, but using 42.2k is same problem.

I think that my board has initial sequence problem.

What should i do?

0 Bill Johns over 11 years ago in reply to chankyu kim

TI__Guru* 75866 points

The low power standby or Snooze cycle will start with a short pulse out of Pin 3. This will turn on FET Q4 and discharge the timing capacitor C22. At that point U5, 3.3V Reg EN goes low and voltage is removed from the BQ500212A. C22 will recharge though R25 until U5 turns back on. BQ500212A turns back on and pings the TX coil if no RX is there the cycle starts over.

0 chankyu kim over 11 years ago in reply to Bill Johns

Prodigy 40 points

You are right.

LED mode1 is OK, any more no probloms.

When I tested LED mode1 before, I had a mistake.

Thank you~

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bq500212a snooze and sleep problem