MP2760GVT - Reducing Current Draw in Sleep

Battery Management
1

Hello,

I am currently developing a product that uses the MP2760GVT charging module with a 4S battery pack. I currently have my device setup to isolate the current draw from the charger chip itself, and I’m seeing around ~560 µA on my meter. But according to the datasheet, I should be able to achieve at least around ~40 µA.

I have tried disabling all major components (ADC, ACGATE, BGATE) and charging, but the draw is still way too high for my product. Could you provide some assistance on configuring the chip and achieving the lowest possible draw in sleep mode?

Here is how I am configuring the chip on initialization:
REG08h = 0x003C
REG09h = 0x00FA
REG0Bh = 0x1000
REG0Eh = 0x0010
REG0Fh = 0xF242
REG10h = 0x2E34
REG12h = 0x3C22
REG14h = 0x0680
REG15h = 0x6900
REG18h = 0x7FFF
REG19h = 0x7FFF

And here are the registers I’m writing to when I bring the device to sleep:
REG0Eh = 0x0010; // Disable ADC
REG10h = 0x2E34; // Disable ACGATE
REG12h = 0x3C22; // Disable BGATE, DC/DC, and charging

To wake it back up, this is what I set:
REG12h = 0x3C73; // Enable BGATE and charging
REG10h = 0x0E74; // Enable ACGATE
REG0Eh = 0x0190; // Enable ADC, continuous mode

Are there any problems with my I2C configuration that would explain this high current draw?

Thank you for the help,

Max

2

Hi Max,

Thank you for posting on the MPS Technical Forum.

You mention isolating the MP2760. Does that mean you have no load and no battery pack attached?

I will look farther into this and get back to you.

Best,

Allison

3

Hello Allison,

Thank you for your response, I appreciate the assistance.

When I say isolating the MP2760, I mean that the 4S battery pack is still connected, but I am temporarily disabling the rest of the system so that my current measurements are not influenced by other components. This allows me to determine how much current is being drawn by the MP2760 itself.

With this setup, I measured approximately 560 µA coming from the MP2760, compared to about 570 µA for the entire device. Based on those measurements, it appears that nearly all of the sleep current is coming from the MP2760.

Thanks,
Max

4

Hi Max,

Thank you for the clarification. With only the battery present (no adapter connection), you are on the right track needing to disable BGATE, ACGATE, and the ADC.

What you are writing to REG12h when bringing the device to sleep looks incorrect. Change the value to:

REG12h = 0x3C12

BGATE was not disabled with the current value. Let me know if this changes the sleep current value.

Best,

Allison

5

Allison,

I have an important update. After going through almost every register individually, I was finally able to get the current draw down to about 44 µA. The one change that reduced this dramatically was the WD_SET bit in REG05h. I was not writing to this register beforehand, so the watchdog must have been enabled in sleep mode by default, despite setting the timer to: “00: Timer disabled” in REG12h. Also you were right to point out BGATE. In my original post I had the BGATE_EN bit set to 1 by mistake, but that was simply for testing and I didn’t realize I wrote out the wrong configuration. So the new sleep configuration is:

REG05h = 0x00E9; // Clear WD_SET
REG12h = 0x3C02; // Disable BGATE, DC/DC, and charging
REG10h = 0x2E34; // Disable ACGATE
REG0Eh = 0x0010; // Disable ADC

I wasn’t able to find an entry in the datasheet for battery standby current with a 4S battery pack (14.8V). Do you know what a typical value might be with this chip?

Thank you!
Max

6

Hi Max,

I’m glad to hear you were able to get the current draw down. 44uA is around the typical range for a 4S battery pack.

Let me know if you have any other concerns.

Best,

Allison