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Author Topic: LTC4020 Charger issues  (Read 5438 times)

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Offline brinbrinTopic starter

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LTC4020 Charger issues
« on: September 09, 2015, 02:38:28 pm »
I am designing a battery charger for 4 LIPOs using LTC4020 as the controller. I am going through a world of hurt getting it to work.  So far I have got the chip to indicate its charging and everything is OK but nothing much happens.  The input mosfet turned on by TG1 does not come on at all.  Am sure I have done something silly, if anyone has any ideas I am all ears.I have attached the schematic of concern
« Last Edit: September 09, 2015, 02:48:05 pm by brinbrin »
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Offline SaabFAN

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Re: LTC4020 Charger issues
« Reply #1 on: September 09, 2015, 03:49:33 pm »
From a first glance, without checking the datasheet, I would say that you forgot to connect the BOOST-Circuit to Vin.
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Offline brinbrinTopic starter

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Re: LTC4020 Charger issues
« Reply #2 on: September 10, 2015, 03:03:29 am »
When VIN is lower than VOUT during step-up (boost) operation, switches Q4 and Q5 perform the PWM required for accommodating power conversion. Q2 would
conduct continuously and Q1 would stay off,
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Offline Jay_Diddy_B

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Re: LTC4020 Charger issues
« Reply #3 on: September 10, 2015, 03:19:56 am »
Hi,

Do you have something connected to the NTC pins?

Try a 10K resistor on the NTC pin to ground.

Jay_Diddy_B

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Offline brinbrinTopic starter

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Re: LTC4020 Charger issues
« Reply #4 on: September 10, 2015, 03:21:59 am »
When nothing is connected to the ntc pin it still should work, in my case i have hooked up a typical 10k thermistor
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