Pioneer Electronic Corporation

Tomy Company, Ltd.

Akio Ozawa

Satoshi Ishii

Susumu Sueyoshi

Kikuo Ishikawa

Kiyomi Yatsuhashi

Masamichi Yumino

Hideo Ito

Masaharu Sakamoto

Keishi Sato

Keishi Saito

Masatsune Sasaki

Katsumi Ishikawa

Susumu Seyoshi

A power supply circuit for an audio power amplifier or an amplifier of similar operation such as a motor driving amplifier. The power supply circuit comprises a first coil having a first terminal connected to a terminal of a DC voltage source and a second terminal connected to an anode of a first diode, a second coil having a first terminal connected to another terminal of said DC voltage source and a second terminal connected to a cathode of a second diode, a first capacitor connected to a cathode of the first diode and the another terminal of the DC voltage, which accumulates a counter electromotive force generated in the first coil; a second capacitor connected to an anode of the second diode and the another terminal of the DC voltage source, which accumulates a counter electromotive force generated in the second coil; opening and closing device connected across the anode of the first diode and the cathode of the second diode, performing an opening and closing operation, and opening and closing control device connected to the opening and closing device, for controlling the opening and closing operation of the opening and closing device, and amplification device connected across a cathode of the first diode and an anode of the second diode.

Power supply circuit

The present invention provides a BTL amplifier device with low power consumption and high efficiency which comprises two units of amplifier, a transistor, and a load resistor, and is driven as claimed in output from an operational amplifier as well as from an inverting amplifier. Signals at both edges of the load resistor are supplied to a differential NFB circuit and a fed-back output is inputted to one of the operational amplifiers, while an output signal from the operational amplifier is converted by an absolute value circuit, and then a DC voltage is superimposed on the absolute value signal in a voltage shifting circuit. Voltage from a voltage divider for dividing an output voltage from the voltage shifting circuit and a power voltage to 1/ gain (G) of the two units of amplifier is supplied to a pulse width control circuit, which is compared to a signal from a triangular oscillator so that the pulse width control circuit supplies the compared voltage to a step-up chopper circuit having a pulse width as claimed in a difference between the two voltages, and the chopper supplies a power voltage according to the output voltage.

Low power consuming balanced transformer less amplifier device

A travelling toy vehicle is provided having an external body in the shape of a dump truck or other vehicle. An internal gear box, or frame, drives two wheels on an axle. The frame contains a vibrating mechanism and rocks left and right by the motion of a spur gear disposed between two cylindrical force receiving pieces attached to the external body of the travelling toy vehicle. A power transmission route change mechanism couples driver power from a motor to the vibrating mechanism for a predetermined period of time to simulate ideling of the vehicle. Thereafter, the drive power is coupled to the travelling mechanism to provide forward movement of the travelling toy vehicle. Electrical power to the motor is switched on and off by pressing down against the rear portion of the travelling toy vehicle. An operation restricting lever mounted at the rear of the vehicle prevents the switching on of electrical power when the toy is being stored and allows manual use of the toy without propulsion by the motor.

Travelling toy vehicle with simulated startup vibration

Voice changing amusement microphone

A push-pull amplifer circuit using bipolar transistors in which non-linear distortion caused by the base-emitter voltages of the amplifying transistors of the circuit is eliminated without the use of negative AC feedback and in which variations in a DC output level at the output terminal of the amplifier are detected and fed back to the input side of the amplifier whereby the stability of the circuit at very low frequencies is remarkably improved. A first amplifier stage includes a first transistor having a base to which an input signal is applied and a second transistor the base of which is coupled to an output of the first transistor with the second transistor being of the opposite conductivity type of the first transistor. A current mirror circuit supplies currents to the first and second transistors with the currents thus supplied having a constant ratio. A second amplifying stage is provided having the same construction. A load is coupled to be driven by the current flowing through the first transistor in the first amplifying stage and by the corresponding transistor in the second amplifying stage. Variations in the output of the circuit are detected to provide a DC feedback voltage which is coupled back to emitter circuits in the input stages of the amplifier.

Amplifier circuit

A push-pull amplifier circuit using bipolar transistors in which non-linear distortion caused by the base-emitter voltages of the amplifying transistors of the circuit is eliminated without the use of negative AC feedback and in which variations in a DC output level at the output terminal of the amplifier are detected and fed back to the input side of the amplifier whereby the stability of the circuit at very low frequencies is remarkably improved. A first amplifier stage includes a first transistor having a base to which an input signal is applied and a second transistor the base of which is coupled to an output of the first transistor with the second transistor being of the opposite conductivity type to the first transistor. A current mirror circuit supplies currents to the first and second transistors with the currents thus supplied having a constant ratio. A second amplifying stage is provided having the same construction. A load is coupled to be driven by the current flowing through the first transistor in the first amplifying stage and by the corresponding transistor in the second amplifying stage. Variations in the output of the circuit are detected to provide a DC feedback voltage which is coupled back to emitter circuits in the input stages of the amplifier.

An amplifier circuit in which the non-linear distortion of the amplifier transistors caused by non-linear base-emitter input and output characteristics is eliminated without the use of negative feedback. A first transistor and a second transistor of opposite conductivity type are coupled with the output of the first transistor connected to the base of the second transistor and with an input signal applied to the base of the first transistor. Currents are applied to the first and second transistors, such as with the current mirror circuit, in such a manner that the ratio of the currents is a predetermined constant value. Bias voltages are applied to the circuit such that the ratio of the collector-emitter voltage of the first transistor to the collector-emitter voltage of the second transistor is the reciprocal of the predetermined constant value.

Amplifier

The response time of an ordinary or differential transistor switching circuit controlled by the charging of a capacitor C.sub.1 is shortened by rapidly charging the capacitor through a transistor Q.sub.6 connected in parallel with the charging resistor R.sub.1 of the capacitor. The transistor is rendered conductive before the differential switching region is reached in response to the capacitor charge reaching a predetermined level, whereby the charging curve thereafter follows a steep rise to sharply reduce the switching time.

Transistor switching circuits with shortened response times

The response time of an ordinary or differential transistor switching circuit controlled by the charging of a capacitor C.sub.1 is shortened by charging the capacitor through a constant current source comprising a transistor Q.sub.6, a resistor R.sub.1 and diodes D.sub.1, D.sub.2, to thereby provide a sharp transfer characteristic. The charging time may be even further shortened by increasing the constant current supply at an intermediate threshold level using a further ordinary or differential transistor switching circuit, thereby providing a break in the response characteristic and increasing its slope after the threshold point.

Transistor switching circuit with shortened response time

A muting circuit for loudspeakers is operable to disconnect a loudspeaker from an amplifier immediately upon a power supply being interrupted. The muting circuit includes an around-zero-volt detection circuit for detecting around the zero volt level of a commercial AC voltage. An RC time constant circuit is controlled by the output of the around-zero-volt detection circuit to either charge or discharge the capacitor in the RC time constant circuit only when the around zero volt level is detected. A threshold circuit is connected to the RC time constant circuit and operates a loudspeaker relay when the charge on the capacitor either exceeds or decreases below a predetermined level.

Muting circuit for loudspeaker

A Schmitt trigger circuit including transistors Q12 and Q13 having a common emitter resistor R3 is thermally coupled to a power amplifier A in a monolithic IC chip, and the base of Q12 is biased at a cutoff potential under normal operating conditions. When the temperature rises to a first predetermined level V.sub.BE of Q12 drops below its biasing potential owing to the temperature characteristic of Q12, whereby Q12 conducts, which cuts off Q13 and, through transistor Q14, disables the amplifier. The common emitter feedback provides a thermal hysteresis characteristic, whereby Q12 is not cut off again until the temperature drops below a second predetermined level.

Growing community of inventors

Tokyo, Japan

Akio Ozawa