摘要：代替通常的晶体管在功率放大器电路的分流稳压器（ U1 ） ，提高了限流精度。Maxim > App Notes > CIRCUIT PROTECTION POWER-SUPPLY CIRCUITS Keywords: shunt regulator, current limit, power amplifier, adjustable shunt regulator Jul 26, 2006 APPLICATION NOTE 3867 Shunt Regulator Improves PA's Current-Limit Accuracy Abstract: Substituting a shunt regulator (U1) for the usual transistor in this power-amplifier circuit improves the current-limit accuracy. Adding current-limiting circuitry to an emitter follower protects both the pass transistor and downstream circuitry from excessive current damage. The classic way to implement such current limiting is to add a ballast resistor between the pass transistor's emitter and the circuit output, and then monitor the resistor drop with a small- signal transistor. See R4 and Q2 in the power amplifier (……