电压计算

/*
 *     __V__
 *       |
 *      R1
 *       |--->ADC
 *      R2
 *     __|__
 *      GND
 * Vadc = R2/(R1+R2) * Vbattery;
 *
 * Ref = 3.3V;
 * 12bit ADC max value = 4095;
 *
 * 3.3/4095 = Vbattery * (R2/(R1+R2) / adc_value;
 *
 * Vbattery = adc_value * 3.3 / 4095 / (R2/(R1+R2));
 * Vbattery = adc_value * 3.3 * (R1+R2) / (R2 * 4095);
 *
 * R1 = 470;
 * R2 = 22;
 *
 * Vbattery = adc_value * 3.3 * (470+22) / (22 * 4095);
 *          = adc_value * 3.3 * 492 / 90090;
 *          = adc_value * 1623.6 / 90090;
*/

/*
 * @brief convert the adc value to voltage
 * @param adc_value the adc value result
 * @retval valtage(mV)
 */
uint32_t voltage_convert(uint32_t adc_value)
{
    uint32_t voltage;

    voltage = adc_value * 1623.6 * 1000 / 90090;

    return voltage;
}

INA181电流检测

/*
 * INA181A2:
 *
 * Vo = (Iload * Rsense * GAIN) + Vref
 *
 * Vref = 0;
 * GAIN = 50; // INA181A2
 * Rsense = 0.01 Ohm (10mΩ)
 * Vo = 3.3/4095 * adc_value;
 *    = 3.3 * adc_value / 4095;
 *
 * Iload = Vo / Rsense / GAIN
 *       = 3.3 * adc_value / 4095 / 0.01 / 50;
 *       = 3.3 * adc_value / 4095 * 100 / 50;
 *       = adc_value * 330 / (4095 * 50);
 *       = adc_value * 330 / 204750;
 */

/*
 * @brief convert adc value to current(mA)
 * @param adc_value the adc result value
 * @retval current value(mA)
 */
uint32_t current_convert(uint32_t adc_value)
{
    uint32_t current;

    current = adc_value * 330 * 1000 / 204750;

    return current;
}

NTC温度计算

// ToDo