Driving circuit with switching element on static current path, and printer using same

A driving circuit driving a plurality of driven elements according to externally supplied driving data, comprising:

• a plurality of drive output circuits having respective driving transistors coupled in series with respective driven elements, supplying driving current to the respective driven elements responsive to the driving data and a control voltage, said driving transistors being switched on and off responsive to the driving data and said driving transistors being driven by the control voltage when switched on;
• a transfer circuit coupled to said drive output circuits, transferring said driving data to said drive output circuits;
• a control-voltage generating circuit coupled to said drive output circuits, generating said control voltage by causing current to flow on a static current path the driving current supplied through said driving transistors to said driven elements having a fixed relationship to the current flowing on the static current path;
• a transistor coupled in series with said node on said static current path, driven by said control voltage;
• and
• a switching element disposed between said transistor and said node on said static current path for receiving a standby command, opening said static current path when said standby command is received, and closing said static current path when said standby command is not received, the control-voltage generating circuit including:
• an operational amplifier having an input terminal coupled to a node on said static current path and an output terminal at which said control voltage is generated said operational amplifier comprising;
• a first current-source transistor supplying a control current responsive to a bias voltage;
• a resistive element coupled in series with said first current-source transistor, generating said bias voltage by conducting said control current;
• at least one second current-source transistor driven by said bias voltage;
• a first switching transistor coupled to said resistive element in a series with said first current source transistor, switched on when said first current-source transistor is switched on, and switched off when a said switching element receives said standby command;
• and
• a second switching transistor coupled to said resistive element in parallel with said first current source transistor, switched off when said first switching transistor is switched on, and switched on when said first switching transistor is switched off, altering said bias voltage and thereby switching off said second current-source transistor when said switching element receives said standby command.