Lithium battery charger / power switch IC...

D

Dave Jordan

Guest
I\'ve done a few designs recently that are powered from a single 3.7V
lithium cell which is recharged from USB. The design has always ended
up with several ICs and a few discrete FETs and diodes to do the power
ON/OFF switch.

Does anybody know of a single IC with the following features:

1. Battery under/over voltage and over current protection, the
equivalent of a DW01 and SC8205.
2. Charging from 5V at up to 500mA, with the current set by a
resistor. A status output for charging complete would be useful. The
equivalent of an MCP73832 (or many other parts).
3. An \'Output\' pin which is connected to 5V when the 5V supply is
present and to the battery when the 5V supply is not present, with
zero voltage drop from the battery to the output.
4. An active low enable input which turns on the Output pin. The
battery should continue to charge with the output disabled.

Some nice additions would be:

5. Multiple enable pins. One for a switch to initially turn on power,
a second for a processor to hold power on until it\'s ready to switch
off. The processor needs to read the state of the switch so I can\'t
just bypass it with a FET.
6. A switched battery output for voltage monitoring, turned off when
the output is off to avoid discharge via the monitoring circuitry.


I can get \'1\' if I use a protected cell but it would be nice to not
have to rely on that.
I can get \'2\' & \'3\' by using something like an MCP73871. I can\'t quite
get \'4\' as the enable pin also disables charging when the output is
off.

This application can\'t be that uncommon, it seems like there should be
a single part which does this, probably in something like an SO-8
package.


Dave.
 
On 11/17/2020 11:38 AM, Dave Jordan wrote:
I\'ve done a few designs recently that are powered from a single 3.7V
lithium cell which is recharged from USB. The design has always ended
up with several ICs and a few discrete FETs and diodes to do the power
ON/OFF switch.

Does anybody know of a single IC with the following features:

1. Battery under/over voltage and over current protection, the
equivalent of a DW01 and SC8205.
2. Charging from 5V at up to 500mA, with the current set by a
resistor. A status output for charging complete would be useful. The
equivalent of an MCP73832 (or many other parts).
3. An \'Output\' pin which is connected to 5V when the 5V supply is
present and to the battery when the 5V supply is not present, with
zero voltage drop from the battery to the output.
4. An active low enable input which turns on the Output pin. The
battery should continue to charge with the output disabled.

Some nice additions would be:

5. Multiple enable pins. One for a switch to initially turn on power,
a second for a processor to hold power on until it\'s ready to switch
off. The processor needs to read the state of the switch so I can\'t
just bypass it with a FET.
6. A switched battery output for voltage monitoring, turned off when
the output is off to avoid discharge via the monitoring circuitry.


I can get \'1\' if I use a protected cell but it would be nice to not
have to rely on that.
I can get \'2\' & \'3\' by using something like an MCP73871. I can\'t quite
get \'4\' as the enable pin also disables charging when the output is
off.

This application can\'t be that uncommon, it seems like there should be
a single part which does this, probably in something like an SO-8
package.


Dave.
Click to expand...

Try looking at Analog Device\'s selection:

<https://www.analog.com/en/products/power-management/battery-management.html>

And for the feature you\'re looking for where it automatically switches
over to an aux voltage when it\'s available I believe you want to click
to filter by devices that include \"PowerPath\"
 
On Tuesday, November 17, 2020 at 8:38:41 AM UTC-8, Dave Jordan wrote:
I\'ve done a few designs recently that are powered from a single 3.7V
lithium cell which is recharged from USB. The design has always ended
up with several ICs and a few discrete FETs and diodes to do the power
ON/OFF switch.

Does anybody know of a single IC with the following features:

1. Battery under/over voltage and over current protection, the
equivalent of a DW01 and SC8205.
2. Charging from 5V at up to 500mA, with the current set by a
resistor. A status output for charging complete would be useful. The
equivalent of an MCP73832 (or many other parts).
3. An \'Output\' pin which is connected to 5V when the 5V supply is
present and to the battery when the 5V supply is not present, with
zero voltage drop from the battery to the output.
4. An active low enable input which turns on the Output pin. The
battery should continue to charge with the output disabled.

Some nice additions would be:

5. Multiple enable pins. One for a switch to initially turn on power,
a second for a processor to hold power on until it\'s ready to switch
off. The processor needs to read the state of the switch so I can\'t
just bypass it with a FET.
6. A switched battery output for voltage monitoring, turned off when
the output is off to avoid discharge via the monitoring circuitry.


I can get \'1\' if I use a protected cell but it would be nice to not
have to rely on that.
I can get \'2\' & \'3\' by using something like an MCP73871. I can\'t quite
get \'4\' as the enable pin also disables charging when the output is
off.

This application can\'t be that uncommon, it seems like there should be
a single part which does this, probably in something like an SO-8
package.


Dave.
Click to expand...

How about this:

https://www.ablic.com/en/doc/datasheet/battery_protection/S82A1A_E.pdf

I think you can detect the end of charging condition from the VM pin.
DO and CO are control pins.
 
On Tue, 17 Nov 2020 11:51:30 -0500, bitrex <user@example.net> wrote:

On 11/17/2020 11:38 AM, Dave Jordan wrote:
I\'ve done a few designs recently that are powered from a single 3.7V
lithium cell which is recharged from USB. The design has always ended
up with several ICs and a few discrete FETs and diodes to do the power
ON/OFF switch.

Does anybody know of a single IC with the following features:

1. Battery under/over voltage and over current protection, the
equivalent of a DW01 and SC8205.
2. Charging from 5V at up to 500mA, with the current set by a
resistor. A status output for charging complete would be useful. The
equivalent of an MCP73832 (or many other parts).
3. An \'Output\' pin which is connected to 5V when the 5V supply is
present and to the battery when the 5V supply is not present, with
zero voltage drop from the battery to the output.
4. An active low enable input which turns on the Output pin. The
battery should continue to charge with the output disabled.

Some nice additions would be:

5. Multiple enable pins. One for a switch to initially turn on power,
a second for a processor to hold power on until it\'s ready to switch
off. The processor needs to read the state of the switch so I can\'t
just bypass it with a FET.
6. A switched battery output for voltage monitoring, turned off when
the output is off to avoid discharge via the monitoring circuitry.


I can get \'1\' if I use a protected cell but it would be nice to not
have to rely on that.
I can get \'2\' & \'3\' by using something like an MCP73871. I can\'t quite
get \'4\' as the enable pin also disables charging when the output is
off.

This application can\'t be that uncommon, it seems like there should be
a single part which does this, probably in something like an SO-8
package.


Dave.


Try looking at Analog Device\'s selection:

https://www.analog.com/en/products/power-management/battery-management.html

And for the feature you\'re looking for where it automatically switches
over to an aux voltage when it\'s available I believe you want to click
to filter by devices that include \"PowerPath\"
Click to expand...

Yes, I\'ve looked at those and similar ones from TI. The LTC3553 in
particular is very close to what I need. I really like the pushbutton
input and its debounced output.

It\'s missing the battery protection though and it\'s a bit expensive
and seemingly hard to get.

I was looking for something simpler. It\'s got a built-in LDO and Buck
DC-DC which I don\'t really need. It would be useful in some cases, but
it\'s only 150mA/200mA which is not enough for some designs.

It\'s on the list of potential parts.


Dave.
 
On Wednesday, November 18, 2020 at 12:46:14 AM UTC-8, Dave Jordan wrote:
On Tue, 17 Nov 2020 11:51:30 -0500, bitrex <us...@example.net> wrote:

On 11/17/2020 11:38 AM, Dave Jordan wrote:
I\'ve done a few designs recently that are powered from a single 3.7V
lithium cell which is recharged from USB. The design has always ended
up with several ICs and a few discrete FETs and diodes to do the power
ON/OFF switch.

Does anybody know of a single IC with the following features:

1. Battery under/over voltage and over current protection, the
equivalent of a DW01 and SC8205.
2. Charging from 5V at up to 500mA, with the current set by a
resistor. A status output for charging complete would be useful. The
equivalent of an MCP73832 (or many other parts).
3. An \'Output\' pin which is connected to 5V when the 5V supply is
present and to the battery when the 5V supply is not present, with
zero voltage drop from the battery to the output.
4. An active low enable input which turns on the Output pin. The
battery should continue to charge with the output disabled.

Some nice additions would be:

5. Multiple enable pins. One for a switch to initially turn on power,
a second for a processor to hold power on until it\'s ready to switch
off. The processor needs to read the state of the switch so I can\'t
just bypass it with a FET.
6. A switched battery output for voltage monitoring, turned off when
the output is off to avoid discharge via the monitoring circuitry.


I can get \'1\' if I use a protected cell but it would be nice to not
have to rely on that.
I can get \'2\' & \'3\' by using something like an MCP73871. I can\'t quite
get \'4\' as the enable pin also disables charging when the output is
off.

This application can\'t be that uncommon, it seems like there should be
a single part which does this, probably in something like an SO-8
package.


Dave.


Try looking at Analog Device\'s selection:

https://www.analog.com/en/products/power-management/battery-management.html

And for the feature you\'re looking for where it automatically switches
over to an aux voltage when it\'s available I believe you want to click
to filter by devices that include \"PowerPath\"

Yes, I\'ve looked at those and similar ones from TI. The LTC3553 in
particular is very close to what I need. I really like the pushbutton
input and its debounced output.

It\'s missing the battery protection though and it\'s a bit expensive
and seemingly hard to get.

I was looking for something simpler. It\'s got a built-in LDO and Buck
DC-DC which I don\'t really need. It would be useful in some cases, but
it\'s only 150mA/200mA which is not enough for some designs.
Click to expand...

Most designs using these chips have external by-pass mosfets to get higher current. I am using a bms board using this and two back-o-back p-channel 4925 (for 4A). I guess putting equivalent mosfet in the chip would be too expensive.
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top