可調的實驗電源: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/1000?Ωof 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.
圖30給出了一個正負輸出均可調的電源電路。基準電壓源由兩個電壓跟隨器組成,跟隨器的輸入是精密恒流源的電流在參考電阻上的壓降。本電源的輸出電壓從±5V至±35V可調,負電壓跟隨正電壓一起變化,R6/R12(原文中為R6/R7,疑為作者筆誤——譯者)決定了二者絕對值之比。
正負電源分別由電阻R6和R12調整,調整率都是1V/1000Ω。正電壓參考源對地的輸出電壓為+2V至+38V,負電壓整流器對地的輸出電壓為-38V至0V。由于使用了放大器LM107(原圖中為LM101,不知是否為作者筆誤——譯者),此電路具有了短路保護能力。當用這個電源測試集成電路時,這種限流能力可以為被測電路提供保護。
此電路配接較低的容性負載時,可選用內部補償型運放。如果需要接較大的容性負載,就要選用外部補償型運放,并且為了提高穩定性還需要進行過補償。在運放的輸入端與地之間加接0.1μF至1.0μF大小的去耦電容可以降低電源的噪聲。
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