Part Number: BQ25606
Hi, i am recently working on a device wich need an standalone IC charger, for this purpose i choose the BQ25606. For start i use the web tool of TI to design it with success and now i am testing it on a PCB. The schematics are as follows:
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My problems are as follow:
I am using an standar NTC of 10k as TI recomends on the design, so the working temperature will be from 0 to 60ºC. But the charger at 5V only draws 0.25A. Not the 3A that i set when a unknow charger its connected to it, actually i am using a Siglent Power supply to control all this steps. At room temperature (about 26ºC) i have 2.521V into the TS point.
If i set a 9V the IC takes a total of 1.29A and go down really fast(about 1 minut) to reach 0.79A. The VBAT=3.55V. On this process the charger IC get really hot, hard to stay with the finger on it, so as the human body feels pain at 65ºC, i suppose that this will be working about 80-100ºC. It's that behaviour normal?.
Status leds:
Actually the project requires the status leds PG and STAT to be working when we have the USB Charger connected, not all the time. For it i connect the voltage to drive the leds to the VBUS input, but when i disconnect the VBUS power supply the IC output 4.256V through the VBUS pin. How could this be possible? in theory this is an input, maybe the diode of the JFET its going backward?, should i add a diode to block it?(but with that a 5V will be never reach exactly). With this issue i cannot use this solution, becasue the status leds will be always on.
The desire behaivour for this product on the status leds is as follows:
Leds OFF-> No charger input connected.
Charger input connected-> Leed of PG on and Led of status showing the status.
If i disconnect the Charger input, then the leds should go off, as there are no VBUS input.
Regards, Carlos.
