Efficient Vccp supply with regulation for voltage control

摘要

A highly efficient compact multiple output voltage generation circuit is designed for use in integrated circuit devices such as DRAMs which require multiple internal voltage supplies for optimum performance. An oscillator is connected to a primary coil of a microtransformer. The microtransformer secondary coil has multiple taps one of which is connected to ground. A second transformer tap is connected to a transformer output node. The oscillating transformer output signal is capacitively coupled to a voltage rectifier. The input to the rectifier is biased to one diode drop below Vcc. The output of the rectifier is an internal supply voltage greater than ground. Another transformer tap is connected to a negative oscillation output node. The negative oscillating signal is rectified to produce a negative internal supply voltage. The voltage generation circuit operates effectively at low Vcc input levels where capacitor based voltage pumps often fail. The circuit is compatible with CMOS manufacturing processes.