CONSTANT CURRENT LOAD CIRCUIT

摘要

PURPOSE:To reduce the electric power capacitance of a Zener diode as well as the heat dissipation, by securing a constant level of the load current regardless of a change of the threshold current of a laser diode for an optical intermediate repeater. CONSTITUTION:The voltage proportional to a bias current IB which is supplied from a DC/DC converter 14 is produced across a resistance 16. This voltage is inverted amplifier 17 and supplied to a DC/DC converter 18. Then a compensating current Ix flows to an earth from a power supply. As a result, the load current can be kept at a certain level regardless of a change of the threshold current of a laser diode 13.