PULSE WIDTH MODULATION AMPLIFIER

PURPOSE:To stabilize the working of a pulse width modulating circuit, by connecting the electrode of one side of each MOSFET to a common output terminal and providing a unidirectional element between the common output terminal and a power supply terminal corresponding to the electrode of the other side to prevent a reverse current. CONSTITUTION:The pulse width moldulatingon signal is applied to the gates of P and N channel enhancement type MOSFETs Q1 and Q2. The common-connected electrode of one side of the FETs Q1 and Q2 is connected to an LPF, and the output of the LPF is supplied to a load RL. A reverse current preventing circuit containing resistances R1 and R2 connected in parallel to diodes D1 and D2 is provided between the electrode of the other side of FETs Q1 and Q2 and an power supplies -VCC and -VCC respectively. The diodes D1 and D2 use a Schottky barrier diode respectively. Then the backward current produced in an ON period of the FETs Q1 and Q2 is supplied to the diodes D1 and D2. As a result, the nonlinear distortion due to a voltage drop of an output pulse is prevented to improve the distortion factor.