BQ24650: Burst charging possible?

Jasper Sikken59

Part Number: BQ24650

I found that under low light conditions the charge efficiency drops dramatically.

Is it possible to apply burst/pwm charging?

The way it works is that the charger is disables as soon as charging stops, then the solar panels voltage rises again until a threshold is reached and then the charger starts working again (efficiently).

over 8 years ago

0 Alen%2520Chen over 8 years ago

TI__Intellectual 2320 points

Hi Jasper,

What Kind of battery you want to charge? Generally, BQ24650 is suited to CC/CV charging. If the Burst/PWM frenquency is quite low you can repeatedly disable/enabel charger to realize this function.

BQ24650 regulates the input volatage to a achieve maximum power point tracking.

Alen

0 Jasper Sikken59 over 8 years ago in reply to Alen%2520Chen

Prodigy 60 points

Charging a single 4.2V battery. Do you have a referenc design that includes burst/PWM charging?

0 Alen%2520Chen over 8 years ago in reply to Jasper Sikken59

TI__Intellectual 2320 points

Generally, Li-ion/polymer battery does not need Burst/PWM charging. does not much affect the life time of battery. So why do you want to Burst/PWM charging?

0 Jasper Sikken59 over 8 years ago in reply to Alen%2520Chen

Prodigy 60 points

I don't need burst charging for the battery, I want bursts because I want to keep the charger running efficient.
The reason is that under low light conditions the charging efficiency becomes really low, like 40%.
A method to keep the charger run efficient is to disable charging when the voltage drops too much, then the panel voltage raises again and it charges a large capacitor and when it is 1-2V volt above Vmpp it gets re-enabled and the the charger shortly runs very efficently from the capacitor until the voltage falls under a threshold. Do you know such a circuit around BQ24650?

0 Alen%2520Chen over 8 years ago in reply to Jasper Sikken59

TI__Intellectual 2320 points

How about the spec of the solar panel( VMPPT, open circuit voltage, power... ) and the charge current? I suggest you use a small FET(Low Qg) and large inductance to increase efficiency. Check out page 17, 22 of the datasheet. Hope this works for you.

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BQ24650: Burst charging possible?