BL652 vs nRF52832 DK - Current Draw Configuration Differences

RE: BL652 vs nRF52832 DK - Current Draw Configuration Differences

Simonr — Mon, 04 Apr 2022 08:21:05 GMT

Sorry about the late reply, but I've been out of office for the last few days, and are just getting to my backlog.

Just to make sure, you set the defines I mentioned to 0 instead of 1 in your sdk_config.h file, right?

By the GPIOs being left "open", are they in a floating state? If they are, and they're connected to peripheral devices, that might explain the current draw. As explained in the nRF52 power optimization guide I linked to earlier, the default "from reset" state of GPIOs are as disconnected inputs. Have you configured them as something else? Unused pins should be left in their default state and physically disconnected to draw no current.

Best regards,

Simon

RE: BL652 vs nRF52832 DK - Current Draw Configuration Differences

smartventSystems — Tue, 29 Mar 2022 18:33:01 GMT

Hello,

I made those changes to the sdk_config.h, ensured that the sdk_config was the one that was being used, and it still draws the same current (~0.5mA).

Are there any other peripherals that might be drawing power? All of the GPIO pins are left open.

RE: BL652 vs nRF52832 DK - Current Draw Configuration Differences

Simonr — Mon, 28 Mar 2022 09:14:35 GMT

Indeed, scanning will draw a lot of current, and the ~0.5mA current consumption is very likely a peripheral (like the UART or similar) drawing current. Can you try turning off the defines enabling logging in your sdk_config.h file? Here are the ones I found that are enabled in your attached sdk_config.h file:

#define NRF_LOG_ENABLED 1

#define NRF_SDH_BLE_LOG_ENABLED 1

#define NRF_SDH_LOG_ENABLED 1

#define NRF_SDH_SOC_LOG_ENABLED 1

#define PM_LOG_ENABLED 1

Best regards,

Simon

RE: BL652 vs nRF52832 DK - Current Draw Configuration Differences

smartventSystems — Wed, 23 Mar 2022 21:26:52 GMT

I was able to find that the uart_init() would draw an extra 350uA or so on the BL652 chip. Is there anything on my code that I could get rid of to reduce power consumption? I thought I already disabled UART logging. Does the UART peripheral usually draw this amount of current? Because I have this active for the development kit, and I'm not getting this much current while it's running there.

static void uart_init(void)
{
    uint32_t                     err_code;
    app_uart_comm_params_t const comm_params =
    {
        .rx_pin_no    = RX_PIN_NUMBER,
        .tx_pin_no    = TX_PIN_NUMBER,
        .rts_pin_no   = RTS_PIN_NUMBER,
        .cts_pin_no   = CTS_PIN_NUMBER,
        .flow_control = APP_UART_FLOW_CONTROL_DISABLED,
        .use_parity   = false,
#if defined (UART_PRESENT)
        .baud_rate    = NRF_UART_BAUDRATE_115200
#else
        .baud_rate    = NRF_UARTE_BAUDRATE_115200
#endif
    };

    APP_UART_FIFO_INIT(&comm_params,
                       UART_RX_BUF_SIZE,
                       UART_TX_BUF_SIZE,
                       uart_event_handle,
                       APP_IRQ_PRIORITY_LOWEST,
                       err_code);
    APP_ERROR_CHECK(err_code);
}

RE: BL652 vs nRF52832 DK - Current Draw Configuration Differences

smartventSystems — Wed, 23 Mar 2022 21:03:18 GMT

Thanks for the prompt reply,

Update: I found out that the BL652 central scanning was drawing the super high 4-5mA. When connected to its peripheral, this drops to around 0.4-0.7mA. This is still much higher than expected though, so I'm sure something is still amiss.

Yes, the project still runs properly on the BL652 even though current draw is off.

I am measuring the current draw via a multimeter right at the power input lead to my board (which is a direct PCB connection into the power pin for the BL652 chip). The average current consumption on the development kit (using the exact same code and configurations) is around 4uA - 15uA when connected.

I have tried switching the DCDC on and off, and it has no visible impact on current draw.

I have attempted some of the applicable suggestions in the link you provided - I have turned off NRF_LOG_BACKEND_UART already prior, and even ran sd_power_system_off(). Doing this, the current draw on my project became 0.7mA (or around the same as if it were connected) . Doing this on the blinky project running on the BL652 still drew current of 13uA instead of the couple hundred nA.

At this point, I'm assuming that there is some peripheral that is running in the background - would there be any peripherals on the BL652 chips that could be activated while the same configurations do not activate them on the development kit?

Are the GPIO outputs draining power on the BL652 when not configured, not connected, and not powered compared to the pinouts on the development kit?

RE: BL652 vs nRF52832 DK - Current Draw Configuration Differences

Simonr — Fri, 18 Mar 2022 14:03:44 GMT

First off, how are you measuring the current consumption on your DK and module exactly? What is the average current consumption on the DK side of things? Does the application still run as expected on the BL652 even though the current draw is off.

An average of 4-5mA sounds incredibly high, and the only thing drawing that amount of current constantly would be the CPU running constantly, so it seems the device doesn't go into sleep mode between advertisements. Simply changing the LF clock source and accuracy should not cause this big of a change in current consumption. However, enabling the DCDC if you don't have the necessary inductors on the DCC pin in your design will likely cause trouble, and might cause a big current draw, but if that's the case, the application shouldn't run as expected either. If you'd like I can do a review of the schematics of your custom board with this module.

Here is a guide on optimizing current consumption on nRF52 designs. Try some of the suggestions there as well to see if you're able to run it as intended.

Best regards,

Simon