我使用的STM32G070RBT6TR采样一个LDO稳压后两个30K分压电阻的电压值1.65V采集的数据偏差满足不了设计要求，看看有没有其他的优化方案，另外采集了Vref值也差不多。

1656.76
1656.76
1655.54
1632.97
1612.84
1592.71
1566.48
1547.57
1532.32
1533.54
1537.81
1539.03
1542.08
1545.13
1548.18
1551.84
1554.89
1557.94
1561.6
1565.26
1567.09
1570.14
1576.85
1580.51
1585.39
1589.66
1593.93
1598.81
1603.08
1607.35
1612.23
1616.5
1620.16
1626.87
1630.53
1634.8
1639.07
1645.17
1648.83
1653.1
1655.54
1639.68
1621.99
1597.59
1577.46
1557.94
1542.08
1529.88
1532.93
1536.59
1539.64
1542.08
1545.13
1548.18
1552.45
1555.5
1559.16
1562.82
1568.31
1571.97
1575.63
1578.68
1582.95
1588.44
1592.1
1598.2
1603.08
1607.35
1611.01
1615.28
1618.33
1626.26
1631.14
1634.8
1640.29
1643.34
1648.83
1654.32
1653.71
1634.19
1612.84
1595.15
1575.02
1548.79
1531.1
1532.32
1535.37
1540.86
1542.08
1546.35
1548.79
1551.84
1555.5
1558.55
1563.43
1565.87
1570.14
1575.02
1578.68
1581.73
1586.61
1591.49
1594.54
1597.59
1601.25
1606.13
1609.18
1614.67
1618.94
1623.21
1626.26
1631.14
1637.24
1640.9
1645.17
1648.83
1653.1
1654.93
1628.7
1611.01
1582.34
1563.43
1543.91
1529.88
1533.54
1536.59
1538.42
1541.47
1545.13
1548.18
1551.84
1554.89
1558.55
1562.21
1565.26
1569.53
1573.8
1577.46
1581.73
1585.39
1589.66
1593.93
1598.2
1602.47
1604.3
1610.4
1613.45
1618.94
1623.21
1627.48
1629.31
1634.8
1639.68
1643.34
1647.61
1651.27
1656.15
1659.81
1653.71
1633.58
1614.67
1597.59
1559.77
1540.86
1530.49
1534.15
1537.81
1540.25
1543.3
1546.35
1550.01
1553.67
1556.72
1560.38
1564.04
1568.31
1572.58
1576.24
1580.51
1585.39
1589.66
1593.93
1598.2
1602.47
1606.74
1611.01
1613.45
1618.33
1622.6
1625.04
1628.09
1633.58
1637.24
1641.51
1647
1649.44
1654.32
1658.59
1662.25
1640.29
1617.72
1596.98
1579.29
1557.33
1536.59
1534.76
1537.2
1540.25
1542.69
1546.96
1547.57
1550.62
1554.89
1557.94
1560.99
1565.87
1569.53
1573.8
1578.07
1582.95
1585.39
1589.66
1593.93
1598.2
1603.08
1606.13
1610.4
1613.45
1618.33
1622.6
1626.87
1631.75
1637.24
1641.51
1645.17
1648.83
1651.88
1656.76
1659.81
1647.61
1629.92
1611.01
1589.66
1568.31
1548.79
1533.54
1535.98
1539.64
1542.08
1544.52
1547.57
1550.62
1554.89
1557.33
1560.99
1565.26

1269.41
1272.46
1275.51
1279.17
1283.44
1286.49
1290.76
1293.2
1293.81
1282.22
1264.53
1252.33
1234.03
1219.39
1202.31
1195.6
1198.65
1200.48
1202.92
1204.75
1210.24
1213.29
1216.34
1218.78
1222.44
1226.71
1228.54
1231.59
1234.03
1237.69
1241.35
1244.4
1247.45
1250.5
1254.16
1257.21
1259.65
1264.53
1267.58
1270.63
1273.68
1277.95
1281.61
1284.05
1288.32
1290.76
1293.2
1290.15
1272.46
1259.04
1238.91
1227.32
1208.41
1194.99
1197.43
1200.48
1202.92
1205.36
1208.41
1212.07
1215.12
1217.56
1220
1222.44
1225.49
1229.76
1232.81
1237.69
1241.35
1244.4
1247.45
1251.72
1255.38
1258.43
1262.09
1264.53
1268.8
1271.24
1275.51
1279.17
1281.61
1285.27
1289.54
1293.2
1294.42
1277.34
1264.53
1246.84
1226.1
1213.29
1199.26
1195.6
1198.65
1200.48
1202.31
1205.36
1209.02
1212.07
1213.9
1216.34
1220
1223.05
1224.88
1227.93
1229.15
1232.2
1235.25
1238.91
1242.57
1245.62
1248.06
1251.72
1254.16
1257.82
1262.09
1267.58
1271.24
1275.51
1278.56
1283.44
1287.71
1290.76
1293.2
1294.42
1276.73
1262.09
1249.89
1233.42
1219.39
1201.09
1194.99
1198.04
1200.48
1202.31
1205.97
1208.41
1210.24
1213.9
1216.95
1218.78
1222.44
1224.27
1227.32
1230.37
1232.2
1235.86
1238.3
1241.35
1245.62
1247.45
1250.5
1253.55
1257.21
1259.65
1262.7
1266.36
1268.8
1272.46
1276.12
1279.78
1282.83
1286.49
1290.76
1295.64
1285.27
1270.02
1252.33
1240.13
1222.44
1205.97
1194.99
1196.21
1199.26
1201.7
1204.14
1206.58
1209.63
1212.68
1215.73
1218.17
1221.22
1224.27
1227.32
1229.15
1232.2
1235.86
1238.3
1240.74
1243.18
1246.23
1249.28
1252.33
1255.99
1258.43
1261.48
1263.92
1267.58
1271.24
1275.51
1278.56
1282.22
1285.88
1289.54
1291.98
1294.42
1287.1
1270.63
1256.6
1238.91
1213.29
1196.82
1195.6
1198.65
1200.48
1203.53
1206.58
1209.02
1211.46
1215.12
1217.56
1220.61
1221.83
1224.88
1228.54
1230.37
1234.03
1236.47
1238.3
1241.35
1244.4
1247.45
1251.11
1254.77
1258.43
1260.87
1263.31
1266.36
1270.02
1273.68
1276.12
1279.78
1282.83
1287.1
1290.15
1293.81
1293.81
1277.34
1264.53
1247.45
1233.42
1218.17
1201.7
1196.21
1199.26
1201.09
1202.92

void MX_ADC1_Init(void) {

/ USER CODE BEGIN ADC1_Init 0 /

/ USER CODE END ADC1_Init 0 /

ADC_ChannelConfTypeDef sConfig = {0};

/ USER CODE BEGIN ADC1_Init 1 /

/ USER CODE END ADC1_Init 1 /

/* Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion) / hadc1.Instance = ADC1; hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4; hadc1.Init.Resolution = ADC_RESOLUTION_12B; hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT; hadc1.Init.ScanConvMode = ADC_SCAN_ENABLE; hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV; hadc1.Init.LowPowerAutoWait = DISABLE; hadc1.Init.LowPowerAutoPowerOff = DISABLE; hadc1.Init.ContinuousConvMode = DISABLE; hadc1.Init.NbrOfConversion = 5; hadc1.Init.DiscontinuousConvMode = DISABLE; hadc1.Init.ExternalTrigConv = ADC_EXTERNALTRIG_T6_TRGO; hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_RISING; hadc1.Init.DMAContinuousRequests = ENABLE; hadc1.Init.Overrun = ADC_OVR_DATA_PRESERVED; hadc1.Init.SamplingTimeCommon1 = ADC_SAMPLETIME_12CYCLES_5; hadc1.Init.SamplingTimeCommon2 = ADC_SAMPLETIME_12CYCLES_5; hadc1.Init.OversamplingMode = ENABLE; hadc1.Init.Oversampling.Ratio = ADC_OVERSAMPLING_RATIO_8; hadc1.Init.Oversampling.RightBitShift = ADC_RIGHTBITSHIFT_3; hadc1.Init.Oversampling.TriggeredMode = ADC_TRIGGEREDMODE_SINGLE_TRIGGER; hadc1.Init.TriggerFrequencyMode = ADC_TRIGGER_FREQ_HIGH; if (HAL_ADC_Init(&hadc1) != HAL_OK) { Error_Handler(); }

/* Configure Regular Channel / sConfig.Channel = ADC_CHANNEL_0; sConfig.Rank = ADC_REGULAR_RANK_1; sConfig.SamplingTime = ADC_SAMPLINGTIME_COMMON_1; if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) { Error_Handler(); }

/* Configure Regular Channel / sConfig.Channel = ADC_CHANNEL_1; sConfig.Rank = ADC_REGULAR_RANK_2; if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) { Error_Handler(); }

/* Configure Regular Channel / sConfig.Channel = ADC_CHANNEL_2; sConfig.Rank = ADC_REGULAR_RANK_3; if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) { Error_Handler(); }

/* Configure Regular Channel / sConfig.Channel = ADC_CHANNEL_3; sConfig.Rank = ADC_REGULAR_RANK_4; if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) { Error_Handler(); }

/* Configure Regular Channel / sConfig.Channel = ADC_CHANNEL_VREFINT; sConfig.Rank = ADC_REGULAR_RANK_5; if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK) { Error_Handler(); } / USER CODE BEGIN ADC1_Init 2 / HAL_ADCEx_Calibration_Start(&hadc1);

HAL_ADC_Start_DMA(&hadc1, (uint32_t )ADC_Buf,5); / USER CODE END ADC1_Init 2 */

}

void HAL_ADC_MspInit(ADC_HandleTypeDef* adcHandle) {

GPIO_InitTypeDef GPIO_InitStruct = {0}; if(adcHandle->Instance==ADC1) { / USER CODE BEGIN ADC1_MspInit 0 /

/ USER CODE END ADC1_MspInit 0 / / ADC1 clock enable / __HAL_RCC_ADC_CLK_ENABLE();

__HAL_RCC_GPIOA_CLK_ENABLE(); /*ADC1 GPIO Configuration PA0 ------> ADC1_IN0 PA1 ------> ADC1_IN1 PA2 ------> ADC1_IN2 PA3 ------> ADC1_IN3 / GPIO_InitStruct.Pin = CUR_C_Pin|CUR_B_Pin|CUR_A_Pin|LK_CUR_Pin; GPIO_InitStruct.Mode = GPIO_MODE_ANALOG; GPIO_InitStruct.Pull = GPIO_NOPULL; HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

/ ADC1 DMA Init / / ADC1 Init / hdma_adc1.Instance = DMA1_Channel1; hdma_adc1.Init.Request = DMA_REQUEST_ADC1; hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY; hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE; hdma_adc1.Init.MemInc = DMA_MINC_ENABLE; hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD; hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD; hdma_adc1.Init.Mode = DMA_CIRCULAR; hdma_adc1.Init.Priority = DMA_PRIORITY_VERY_HIGH; if (HAL_DMA_Init(&hdma_adc1) != HAL_OK) { Error_Handler(); }

__HAL_LINKDMA(adcHandle,DMA_Handle,hdma_adc1); / USER CODE BEGIN ADC1_MspInit 1 /

/ USER CODE END ADC1_MspInit 1 / } }

void HAL_ADC_MspDeInit(ADC_HandleTypeDef* adcHandle) {

if(adcHandle->Instance==ADC1) { / USER CODE BEGIN ADC1_MspDeInit 0 /

/ USER CODE END ADC1_MspDeInit 0 / / Peripheral clock disable / __HAL_RCC_ADC_CLK_DISABLE();

/*ADC1 GPIO Configuration PA0 ------> ADC1_IN0 PA1 ------> ADC1_IN1 PA2 ------> ADC1_IN2 PA3 ------> ADC1_IN3 / HAL_GPIO_DeInit(GPIOA, CUR_C_Pin|CUR_B_Pin|CUR_A_Pin|LK_CUR_Pin);

/ ADC1 DMA DeInit / HAL_DMA_DeInit(adcHandle->DMA_Handle); / USER CODE BEGIN ADC1_MspDeInit 1 /

/ USER CODE END ADC1_MspDeInit 1 / } }

首先考虑一下硬件方面：主要是VREF 的电压纹波。逐次比较型ADC 的分母就是这个电压，它的纹波决定它的比值结果是否稳定。

其次 电阻分压型电路通常阻抗很大，也就意味着电流很小，任何接入的电路都会引起很大电压波动。所以ADC的采样时间一定要足够大。
再次 如果充电时间增加还不能满足，那就需要外部增加一个小电容。具体原理可以参考原厂应用笔记 AN2834

从转换结果来看，误差的确大，基本没有正常工作，应该远不是优化的问题。除非是你的信号本身就飘荡不定。


电源方面，所有电源脚都接对、接好。


注意ADC使用前做下校准, 采样时间适当设置长点。


重点确认下ADC的参考电压，到底是来自外部参考电压还是来自内部VREFBUF的输出。如果选择内部VREFBUF


的话，其输出选择要结合VDD，这些都要确认好。


比方：
– VREF+ around 2.048 V (requiring VDDA equal to or higher than 2.4 V)

– VREF+ around 2.5 V (requiring VDDA equal to or higher than 2.8 V)