In a three-stage Darlington transistor circuit, the base of the middle transistor is connected to the series combination of a resistance and a Zener diode, with the Zener diode anode being connected to the resistance. A voltage divider is provided between the collector and emitter of the power transistor. For reducing the loading and deviation from nominal value of the voltage divider with change of temperature, an auxiliary transistor (T.sub.4) is provided having its base connected to one tap of the voltage divider and its emitter to the cathode of the Zener diode. The collector of the auxiliary transistor is provided in the integrated circuit substrate in common with the collectors of the transistors of the Darlington circuit. The other tap of the voltage divider is provided for emitter-collector clamping voltage purposes.