必须对信号进行电压限制和保护处理,否则将严重损坏MCU。
在高压输入场景(例如12V、24V或更高)下将信号引入灵动MCU的ADC前,必须对信号进行电压限制和保护处理,否则将严重损坏MCU。下面是一套可靠、常用的前端设计方案,适用于灵动MCU进行安全电压采样。核心目标
确保输入信号 经过电压降压与过压保护处理 后,进入ADC的电压始终在 0V ~ Vref(如3.3V)范围内。
推荐的前端保护电路结构
markdown
复制
编辑
高压信号 ── 电阻分压 ──+───> ADC输入
|
钳位二极管
|
GND
1. 电阻分压(必须)
使用一组电阻构建电压分压器,将高压线性压降到 MCU ADC 支持的范围。
设计要点:
选高阻值电阻(如100kΩ量级),减少电流损耗
分压比例由下式决定:
data:image/png;base64,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
示例:
目标:采样 024V 到 03.0V
可选:R1 = 150kΩ,R2 = 20kΩ
data:image/png;base64,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
2. 钳位保护(瞬态/过压防护)
使用 钳位二极管(如TVS或普通肖特基二极管) 在 ADC 输入对 VDD/GND 夹紧,防止输入电压瞬时超过安全范围。
推荐方案:
两极钳位:使用两个肖特基二极管
一个接 VDD(阳极接ADC,阴极接3.3V)
一个接 GND(阴极接ADC,阳极接GND)
或使用一个 双向TVS管(如 PESD3V3L)
作用:
当输入电压超过 VDD + 0.3V,电流被钳位到 VDD
防止 MCU IO 结构中内部ESD二极管被击穿
3. ADC输入端RC滤波(推荐)
电阻 + 电容(典型为 1~10kΩ + 100nF)构成低通滤波器
滤除高频干扰、防止采样尖刺
c
复制
编辑
高压输入 ─ R1 ─+─R2─┬──> ADC
| |
C1 GND
4. 电路设计总览图(示意)
lua
复制
编辑
高压输入(如24V)
|
R1 (150k)
|
+----------+
| |
R2 (20k) TVS or
| 双肖特基
+----+-----+
|
C1=100nF
|
GND
5. 注意事项
项目 说明
电阻功耗 分压电阻会持续消耗功率:P ≈ V²/R<sub>总</sub>,可选 >100kΩ 降低功耗
精度影响 使用1%或更精密电阻,减少分压误差
ADC校准 分压后需要乘以补偿系数恢复原电压
漏电保护 高压设备输入需考虑隔离或保护启动
软件补偿计算示例(以3.3V ADC为例):
c
复制
编辑
#define VREF 3.3
#define ADC_MAX 4095.0
#define R1 150000.0
#define R2 20000.0
float read_voltage(uint16_t adc_val) {
float v_adc = (adc_val / ADC_MAX) * VREF;
return v_adc * (R1 + R2) / R2;
}
总结:高压采样设计要点
设计模块 作用
电阻分压 将高压降至 ADC 支持范围
钳位保护 防止瞬时过压烧毁 MCU
RC滤波 抑制噪声毛刺,提高采样稳定性
软件校正 通过补偿还原真实电压
页:
[1]