AUTOMATIC CURRENT CONTROL APPARATUS OF OUTPUT PORT

摘要

PURPOSE: An automatic current control apparatus of an output port is provided, which makes the most appropriate current value be supplied to an input load, by determining a value of a compensation load automatically as operating a circuit. CONSTITUTION: An equivalent input load(12) receives a supply current(Isupply) supplied from an equivalent output part(1) of a PMOS transistor(PM1) and an NMOS transistor(NM1). A current controlled voltage source(13) is connected to the equivalent input load in parallel and samples the supply current. A voltage measurement circuit part(14) measures a voltage being output through the current controlled voltage source. A register(15) loads a reference voltage value for the equivalent output part to supply a current stably. A comparator part(16) outputs a compensation load selection signal which determines the most appropriate current value, by comparing the reference voltage loaded in the register with a voltage measured in the voltage measurement circuit part. And a number of compensation loads(171-17n) compensate for an input current of the equivalent input load by being selected by the compensation load selection signal of the comparator part.