Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Masaaki Koto

Takuya Ishii

Kazuhito Kimura

Takashi Ryu

Hirohisa Tanabe

Kazuyuki Moritake

Tamotsu Yamamoto

Junichi Morita

Mikio Motomori

Richard Oswald

Naoyuki Nakamura

Makoto Ishimaru

Satoshi Wada

Hiroyuki Miyachi

A load drive circuit with a current bidirectional detecting function includes: a current bidirectional switch connected between a first wire and a second wire and through which a first forward current flows in a direction from the first wire to the second wire and a first backward current flows in a direction from the second wire to the first wire; a forward current detecting switch connected to the first wire and into which a second forward current correlated to the first forward current flowing through the current bidirectional switch flows; a backward current detecting switch connected to the second wire and into which a second backward current correlated to the first backward current flowing through the current bidirectional switch flows.

Load drive circuit with current bidirectional detecting function

The present invention provides a current-mode control step-up converter capable of reducing the minimum duty ratio to a sufficiently small value and facilitating the setting of the maximum duty ratio. The step-up converter comprises a current detectorfor generating a current detection signal Vc corresponding to the current of a rectifier; an error amplifierfor generating an error signal Ve corresponding to an output DC voltage Vo; and a control circuitfor turning ON/OFF the main switchon the basis of the current detection signal Vc and the error signal Ve. The control circuitcomprises a comparatorand a timer circuit. With this configuration, the ON time of the main switchis set at a predetermined value, and the valley value of an inductor current changing in a triangular waveform is controlled. Hence, the OFF time of the main switch is adjusted to stabilize the output. Since the ON time of the main switchcan be set as desired, the minimum duty ratio can be reduced to zero or a sufficiently small value.

Step-up converter

An output circuit includes an output block and a predrive block for driving the output block based on an input signal. The predrive block has a clamp unit connected between the gate terminal of a first output transistor and the gate terminal of a second output transistor to limit the potential of the gate terminal of the first output transistor to a value of not more than a first potential and limit the potential of the gate terminal of the second output transistor to a value of not less than a second potential.

Output circuit for outputting a signal with a high-voltage amplitude

A switching regulator circuit including a high-side switch and a low-side switch; an inductor having a first terminal coupled to a common terminal between the high-side switch and the low-side switch, and a second terminal coupled to an output terminal of the switching regulator circuit; a low-pass filter coupled to the first terminal of the inductor, where the low-pass filter is operative for generating a ramp signal based on the voltage signal present at the first terminal of the inductor; and a hysteretic comparator coupled to the low pass filter, where the hysteretic comparator receives the ramp signal as an input signal, and generates an output signal which is operative for controlling the operation of the high-side switch and the low-side switch.

Hysteretic switching regulator

A level shift circuit has a driving circuit and an output circuit. The driving circuit has a clamp circuit for receiving first and second bias potentials, outputting first and second drive signals which are not less than a reference potential, less than the first bias potential, and complementary to each other, and also outputting third and fourth drive signals which are higher than the second bias potential, not more than a power source potential, and complementary to each other. The output circuit has a first output transistor of a first conductivity type and a second output transistor of a second conductivity type which are connected in series to each other. The first output transistor has a gate for receiving the first drive signal and one electrode for receiving the reference potential. The second output transistor has a gate for receiving the third drive signal and one electrode for receiving the power source potential.

Level shift circuit

A DC-DC converter for converting an input DC voltage to an output DC voltage has a switch element which is turned ON/OFF by a drive signal, a reference voltage source for outputting a first reference voltage when the switch element is ON or outputting a second reference voltage when the switch element is OFF, a capacitive element having one terminal connected to the reference voltage source, a charge/discharge circuit for discharging the capacitive element when the switch element is ON and charging the capacitive element when the switch element is OFF, a switch circuit for short-circuiting the capacitive element when the switch element is turned ON and OFF, and a comparison circuit for comparing the output DC voltage or a voltage at which the output DC voltage is detected with a voltage at the other terminal of the capacitive element and generating the drive signal.

Growing community of inventors

Osaka, Japan

Masaaki Koto