可调的实验电源:Programmable Bench Power Supply
The complete power supply shown in Figure 30 is a programmable positive and negative power supply. The regulator section of the supply comprises two voltage followers whose input is provided by the voltage drop across a reference resistor of a precision current source. Output voltage is variable from ±5V to ±35V. Negative output tracks positive output to within the ratio of R6 to R7.
Programming sensitivity of the positive and negative supply is 1V/1000Ωof resistors R6 and R12 respectively. The output voltage of the positive regulator may be varied from approximately +2V to +38V with respect to ground and the negative regulator output voltage may be varied from - 38V to 0V with respect to ground. Since LM107 amplifiers are used, the supplies are inherently short circuit proof. This current limiting feature also serves to protect a test circuit if this supply is used in integrated circuit testing.
Internally compensated amplifiers may be used in this application if the expected capacitive loading is small. If large capacitive loads are expected, an externally compensated amplifier should be used and the amplifier should be overcompensated for additional stability. Power supply noise may be reduced by bypassing the amplifier inputs to ground with capacitors in the 0.1 to 1.0 μF range.
图30给出了一个正负输出均可调的电源电路。基准电压源由两个电压跟随器组成,跟随器的输入是精密恒流源的电流在参考电阻上的压降。本电源的输出电压从±5V至±35V可调,负电压跟随正电压一起变化,R6/R12(原文中为R6/R7,疑为作者笔误——译者)决定了二者绝对值之比。
正负电源分别由电阻R6和R12调整,调整率都是1V/1000Ω。正电压参考源对地的输出电压为+2V至+38V,负电压整流器对地的输出电压为-38V至0V。由于使用了放大器LM107(原图中为LM101,不知是否为作者笔误——译者),此电路具有了短路保护能力。当用这个电源测试集成电路时,这种限流能力可以为被测电路提供保护。
此电路配接较低的容性负载时,可选用内部补偿型运放。如果需要接较大的容性负载,就要选用外部补偿型运放,并且为了提高稳定性还需要进行过补偿。在运放的输入端与地之间加接0.1μF至1.0μF大小的去耦电容可以降低电源的噪声。
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