- Ask a related questionWhat is a related question?A related question is a question created from another question. When the related question is created, it will be automatically linked to the original question.
Dear,
We are exploring charging IC ,Our application is based to charge 18650 cell with single cell configuration.We will be going to use 5p pack of the battery.
We want charging current of 2 to 2.5A .The source of charging would be 5v/3A charger or 12 v rated DC Adapter,Also IC Current consumption should be less.The consumption of our system is around 30 mA and is battery operated.
We explored some charging IC bq25601,So would this IC suit our application.
Also suggest us some other IC which we suits our application.
Waiting for your response..!!
Dear,
-->The BQ25601 is a good choice if you're using a 5V/3A adapter. However, the default input OVP setting is only 6.5V, which would be an issue if you use a fixed voltage 12V adapter instead.
Thanks for the suggestion...!!
I checked the datasheet it mentions 14 V OVP Setting.So if we set that setting through I2C and use 5V USB Will it cause any problem.Also we are designing a system where two input supply provision is given ,
One is for USB and second one is for DC Adapter.
------x---------------------------------------------x--------------------------------------------
1) Is I2C communication a must for you? If not, you could look into the BQ25606 instead. This device is very similar to the BQ25601, but it's standalone, and the input OVP threshold is 14.2 V.
-->OK,I will look for it.No,I2C Communication is not necessary for us.Yes we require high input voltage so 14 v to 15 V will be good.I will revert back if any query...!!
And one more thing i missed was,the charging ic should generate the output even if my battery is not present.This provision should be also there.
2) You could also look into the BQ2589x family instead, which has a max charge current of up to 5 A. You mentioned that your battery pack is a 1s5p configuration, so if the battery capacity is large, it may be desirable to have a higher charge current in order to allow faster charging.
-->OK,We will check that series.
Hi Tirthal,
1) 3.9 V < VBUS < 13.5 V is the recommended operating range, while 22 V is the absolute maximum safety rating. If VBUS exceeds 22 V, then the IC may be permanently damaged.
VBUS = 15 V will not work because this is higher than the input OVP threshold, as shown below. 15 V will not damage the IC, but there will be no charging.
2) With only an adapter and no battery connected, VSYS will oscillate between 3.7 V and 4.2 V, as shown in the waveform below (VSYS in green and VBAT in yellow). VSYS tracks VBAT, but does not fall below SYS_MIN. The reason for this oscillation is that the BQ25606 continuously enters recharge and termination cycles as the small capacitor from BAT to GND charges and discharges. There is a 250 ms deglitch time for both recharge and termination, which explains the frequency of the oscillation.
On the other hand, if the adapter and the battery are both connected, then the relationship between VSYS and VBAT is shown in Figure 14 below. If VBAT < SYS_MIN, then the BATFET operates in LDO mode, and VSYS will be about 180 mV above SYS_MIN. As VBAT rises above SYS_MIN, the BATFET turns fully on, so VSYS = VBAT (ignoring the Vds voltage drop across the BATFET).
Best regards,
Angelo
Dear,
We have designed the schematic please have a look :
Few question :
-->Like BQ24133 Charging IC which generate 3.3v of voltage from its LDO ,is there any provision the bq25606 generates the voltage when input source is present ?
-->In our schematic that we have designed below are the points that system should achieve:
1)When NO Battery / With Battery the charging IC Should provide the output.(3.7 V to 4.2 V and 1 A Min Of current )
Query :At present we are taking the output from the VSS_BAT_4.2v which will be driving the system.So if battery is not present then will we get Oscillated Output from 3.7 V to 4.2 V. At that (BAT)Pin..?
Or I should Take the input to the system from VSS_CHG_4.2v which is connected to SYS_1,SYS_2 Pin...Please explain Why..?
-->What will be the output at SYS_1,SYS_2 Pin when Adapter Plugged IN (5 V/12 V ) ,With battery?
-->What will be the output at SYS_1,SYS_2 Pin when Adapter Plugged IN (5 V/12 V ) ,Without battery?
-->What will be the output at SYS_1,SYS_2 Pin when Adapter (5 V/12 V ) Not Present ,With battery?
-->How much current will be available through SYS_1,SYS_2 Pin (VSS_CHG_4.2v ) :
1)Adapter + Battery = ? A(Current)
2)Only Battery = ? A(Current)
3)Only Adapter = ? A(Current)
Waiting for your reply...!!
Hi Tirthal,
I've reviewed your schematic. Here are my comments:
1) Please increase the /PG and STAT pull-up resistors (R80 and R81) from 130 Ω to 2.2 kΩ.The reason for this is to reduce the sink current for these pins. For example, the STAT pin's absolute maximum sink current is only 6 mA, but your 130 Ω pull-up resistor could cause about 30 mA of sink current.
2) What is the purpose of R72? R71 already shorts /CE to GND in your schematic.
3) The input to the system should be connected to VSYS (labeled as VSS_CHG_4.2v in your schematic). SYS is the pin voltage that the BQ25606 maintains with its minimum system voltage regulation. Also, if you connected the system to BAT instead, the battery and the system would be shorted. This will prevent the system from powering up if the battery is deeply discharged.
Regarding your other questions:
1) Please see Section 8.3.2.1 in the datasheet for the conditions that must be met in order to enable the REGN LDO.
2) VSYS under various conditions:
With only an adapter: VSYS will oscillate between SYS_MIN + 180 mV and VREG (typically 3.68 V and 4.2 V, respectively).
With only a battery: VSYS = VBAT - Vds of BATFET as long as VBAT > VBAT_DPL.
With both an adapter and a battery: Please refer to Figure 14 in the datasheet to see the relationship between VSYS and VBAT.
3) ISYS under various conditions:
With only an adapter: This depends on the input current limit setting. However, keep in mind that the recommended maximum output current is 3 A, as shown below.
With only a battery: ISYS cannot exceed IBATFET_OCP (6 A minimum value).
With both an adapter and a battery: This also depends on the input current limit setting (similar to the adapter only case). However, the battery can enter supplement mode in order to help power the system.
Lastly, I would recommend ordering a BQ25606 EVM in order to simplify the evaluation process. This will be very helpful in understanding the behavior of the device. Also, if you run into any issues later on, TI will be able to provide more effective support because the customer and I will be able to test things on the same circuit and compare results from the same baseline.
Best regards,
Angelo
