Kabushiki Kaisha Toshiba

Hitoshi Kinoshita

Masaru Hashimoto

Hysteresis circuit

A temperature detection circuit includes first and second current sources and a comparing circuit. A first current source generates a current having a positive temperature coefficient and flowing in a band gap type voltage source. A second current source generates a current having a zero or negative temperature coefficient. The comparing circuit compares the amounts of currents flowing in the first and second current sources to detect the relation between the magnitudes of the compared currents.

Temperature detection circuit used in thermal shielding circuit

A load driving circuit includes a pair of push-pull circuits formed of bipolar transistors. A load is connected between the output terminals of the push-pull circuits and the polarity of a current flowing in the load can be changed to drive the load. The pair of push-pull circuits are controlled by means of an output transistor driving circuit. The output transistor driving circuit includes first and second driving transistors for driving output transistors constituting the push-pull circuits and first and second control transistors for preventing the flow of a through current. The emitter and collector of the first control transistor are respectively connected to the emitter and base of the first driving transistor or the emitter and base of the output transistor arranged on the power source side and constituting one push-pull circuit. The emitter and collector of the second control transistor are respectively connected to the emitter and base of the second driving transistor or the emitter and base of the output transistor arranged on the power source side and constituting another push-pull circuit. The conduction states of the first and second driving transistors are controlled by signals set in an inverted phase. The conduction state of the first and second control transistors are respectively controlled by signals which is in the same phase as the signal for controlling the second and first driving transistors.

Load driving circuit having a pair of push-pull circuits

An amplifying device comprises a differential amplifier stage, which includes a first transistor supplied with an input signal and a second transistor supplied with an output signal as a negative feedback signal, and a third transistor for detecting cutoff of a power supply voltage to be supplied to the differential amplifier stage. The third transistor controls a fourth transistor which sets the potential at the base of the first transistor at the ground level. The base of the first transistor is connected to the base of a fifth transistor, which controls a sixth transistor connected between the ground and the base of the second transistor so that in a power-off state, the fourth and sixth transistors render the potentials at the bases of the first and second transistors to be the ground level.

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Kawasaki, Japan

Hitoshi Kinoshita