npm1300 problem

[sunnyyang]

hi professor,

    The npm1300 is used for power management  on my borad.When VBAT and VBUS are connected simultaneously, the bulk 2 output power supply varies between 1V and 3.3V.When only VBUS is connected, the bulk 2 output voltage is fixed at 3.3V, which meets my expectations.

    The chip version i am using is CAAACA 2335A1.Does this version of the chip have such characteristics that VBAT must be connected?

Here are the DTS fragments:

&arduino_i2c {
npm1300_ek_pmic: pmic@6b {
compatible = "nordic,npm1300";
reg = <0x6b>;

npm1300_ek_gpio: gpio-controller {
compatible = "nordic,npm1300-gpio";
gpio-controller;
#gpio-cells = <2>;
ngpios = <5>;
};

npm1300_ek_regulators: regulators {
compatible = "nordic,npm1300-regulator";
/* limits are set to min/max allowed values */
npm1300_ek_buck1: BUCK1 {
regulator-min-microvolt = <1800000>;
regulator-max-microvolt = <3300000>;
/delete-property/ regulator-init-microvolt;
};
npm1300_ek_buck2: BUCK2 {
regulator-min-microvolt = <1000000>;
regulator-max-microvolt = <3300000>;
regulator-init-microvolt = <3300000>;
regulator-always-on;
regulator-boot-on;
/delete-property/ retention-microvolt;
/delete-property/ enable-gpios;
/delete-property/ retention-gpios;
/delete-property/ pwm-gpios;
};

npm1300_ek_ldo1: LDO1 {
/delete-property/ regulator-min-microvolt;
/delete-property/ regulator-max-microvolt;
/delete-property/ regulator-initial-mode;
/delete-property/ enable-gpios;
};

npm1300_ek_ldo2: LDO2 {
regulator-min-microvolt = <1800000>;
regulator-max-microvolt = <3300000>;
regulator-init-microvolt = <1800000>;
regulator-initial-mode = <NPM1300_LDSW_MODE_LDO>;
regulator-always-on;
regulator-boot-on;
/delete-property/ enable-gpios;
};
};
npm1300_ek_charger: charger {
compatible = "nordic,npm1300-charger";
term-microvolt = <4200000>;
term-warm-microvolt = <4000000>;
current-microamp = <400000>;
dischg-limit-microamp = <1000000>;
vbus-limit-microamp = <500000>;
thermistor-ohms = <10000>;
thermistor-beta = <3380>;
charging-enable;
vbatlow-charge-enable;
};
npm1300_ek_buttons: buttons {
compatible = "gpio-keys";
pmic_button0: pmic_button_0 {
gpios = < &npm1300_ek_gpio 0 GPIO_ACTIVE_HIGH>;
label = "Pmic button switch 0";
zephyr,code = <INPUT_KEY_0>;
};
};
npm1300_ek_leds: leds {
compatible = "nordic,npm1300-led";
nordic,led0-mode = "host";
nordic,led1-mode = "charging";
nordic,led2-mode = "error";
};
};
};

[helsing]

Hi sun yang,

When VBAT and VBUS are connected simultaneously, the bulk 2 output power supply varies between 1V and 3.3V

Do you have any plot from an oscilloscope showing this?

The npm1300 is used for power management  on my borad.

Would you be able to share the schematic of your design? Has anyone at Nordic reviewed your design? We offer a review of the Nordic related part of the design as a free service. If you would like us to do this, we could make the ticket private so that you can add upload the files.