Seiko Epson Corporation

Atsushi Yamada

Katsumi Inoue

Kei Ishimaru

Norikazu Tsukahara

Isamu Moriya

Hideyuki Akanuma

Toshikazu Kuwano

Hisao Sato

Noriaki Sakurada

Ichiro Kobayashi

Isao Shishikura

Yasuhiro Takahashi

A circuit device includes an N-type well on a P-type substrate, a P-type well provided in the N-type well, a circuit element provided in the P-type well, a P-type well provided in an N-type well, and a circuit element provided in the P-type well. A ground power supply voltage is supplied to a P-type well. A power supply voltage different from the ground power supply voltage is supplied to a P-type well. The ground power supply voltage or a first potential that is greater than or equal to the potential of the ground power supply voltage and less than the potential of a high potential-side power supply voltage is supplied to an N-type well.

Circuit device, light source device, and electronic apparatus

A light emission control device includes: a first light emission control circuit outputting a first control signal and a second control signal; and a second light emission control circuit outputting a third control signal and a fourth control signal. The first light emission control circuit controls a phase of the second control signal based on a first PWM signal in a first PWM dimming mode. The second light emission control circuit controls a phase of the fourth control signal based on a second PWM signal in a second PWM dimming mode. The second light emission control circuit outputs the fourth control signal having a phase different from that of the second control signal in a first analog dimming mode and a second analog dimming mode.

Light emission control device, light source device, and projection-type video display apparatus

Provided is a light source apparatus including semiconductor light sources and a current detection resistor connected in series, a power source circuit that allows current to flow thereto, a current detection circuit that detects current flowing to the current detection resistor and outputs a current detection signal, a control circuit that controls the power source circuit such that a voltage of the current detection signal approaches a target value, a bypass circuit connected in parallel to the semiconductor light sources, and including a clamp element having a clamp voltage higher than a maximum voltage during operation of the semiconductor light sources and a bypass resistor connected in series to the clamp element, and allowing current to flow when an open fault occurs in the semiconductor light sources, and detection circuits that respectively detect an open fault in the semiconductor light sources based on an end-to-end voltage of the bypass resistors.

Light source apparatus and projection-type display apparatus

An electronic circuit includes a noise source and an analog circuit and a logic circuit that may be adversely affected by noise. At least a portion of the analog circuit and the logic circuit is formed on a buried impurity layer whose conductivity is different from that of a substrate, and at least a portion of the periphery of that portion is surrounded by an impurity layer that is different from the substrate. Thus, propagation of the noise from the noise source is prevented.

Circuit device and electronic apparatus

A light emission control device includes a power source circuit for a drive circuit that supplies a power for a drive circuit based on an input power, a power source circuit for a control circuit that supplies a power for a control circuit based on the input power, a control circuit, a drive circuit, and a start control circuit. The control circuit outputs a control signal for controlling turning on/off of a switching element. The drive circuit outputs a drive signal for driving the switching element based on the control signal. The start control circuit outputs a start control signal for delaying a timing at which the output of the drive signal is started after the input power is turned on.

A light source device includes: a semiconductor light source; a switching element connected in series to the semiconductor light source; a drive circuit that turns on the switching element when a first control signal based on a PWM signal is in a first logic state; a switching power supply circuit that supplies a current to the semiconductor light source; a current detection element that detects a current flowing through the semiconductor light source and generates a current detection signal; a current detection circuit that sample-holds a current detection signal for a period shorter than an activation period of the PWM signal; an error amplifier that generates an error signal by amplifying the difference between a current control signal and an output signal of the current detection circuit; and a control circuit that generates a second control signal for controlling the switching power supply circuit based on the error signal.

Light source device, projection type display device, and semiconductor device

A light emission control circuit includes a drive circuit that generates a first control signal in order to control a first switching element, and a switching control circuit that generates a second control signal in order to control a second switching element. The switching control circuit maintains the second control signal in an inactivation state in a period in which the first control signal is inactivated in a case where an ON duty ratio of the first control signal is equal to or more than a predetermined value, and maintains the second control signal in an activation state in a part of the period in which the first control signal is inactivated in a case where the ON duty ratio of the first control signal is less than the predetermined value.

Light emission control circuit, light source device, and projection type video display apparatus

With an IC including a driver that drives a large current, its characteristics may be deteriorated or the IC may be broken by heat generated by the large current. By providing a plurality of sensors and disposing some of the sensors so as to be close to an output driver that flows a large current, which is a source of heat generation, an increase in the temperature of the IC can be rapidly detected, and the deterioration of the characteristics of the IC can be prevented by accurately actuating an overheating protection function based on a result of detection. Alternatively, breakage of the IC can be prevented by suppressing overheating.

Circuit apparatus and electronic appliance

A semiconductor device of the invention is a semiconductor device that controls a transistor that controls an electric current that flows through a light emitting element, the transistor including a gate that is connected to one end of a capacitor. The semiconductor device includes: a first terminal that is connected to the gate of the transistor and the one end of the capacitor; a second terminal that is connected to the other end of the capacitor; a first driving circuit that outputs a first control signal to the first terminal; and a second driving circuit that, in order to control the transistor in an on-state or an off-state, activates or deactivates a second control signal, and outputs the second control signal to the second terminal, the second control signal having a potential lower than a potential of the first control signal.

Semiconductor device, light emission control circuit, and electronic appliance

This light emission control circuit controls a first switching element for controlling a current that flows to a light-emitting element connected between a first node and one end of an inductor, and a second switching element for controlling a current that flows from the other end of the inductor to a second node. The light emission control circuit has a driving circuit that generates a first control signal for controlling the first switching element, and a switching control circuit that generate a second control signal for controlling the second switching element, and deactivates the second control signal in order to bring the second switching element into an off-state, during a period during which the first switching element is in an off-state.

Light emission control circuit, light source apparatus, and projection-type video display device

A circuit device includes: a comparator that outputs an output signal that is activated when a potential of an input terminal is lower than a determination level; a switch circuit that is electrically connected between an output node connected to a switching element that enters a conduction state or a non-conduction state according to a drive signal and the input terminal of the comparator, and is in a non-conduction state when the switching element is in a conduction state; and a control circuit that controls a level of the drive signal such that the switching element will not enter a conduction state again based on a period during which or the number of times the output signal of the comparator is activated after the switching element has transitioned from a conduction state to a non-conduction state.

Circuit device, switching regulator, and electronic apparatus

A circuit device includes a first switching circuit that has one end connected to an output node, and turns on and off according to a drive signal, a second switching circuit that is connected in series with an impedance element between another end of the first switching circuit and a node having a predetermined potential, and turns off and on complementarily with the first switching circuit, a comparator circuit that outputs an output signal indicating whether or not a potential of the other end of the first switching circuit is higher than a determination level, and a control circuit that controls a level of the drive signal based on the output signal of the comparator such that the switching element enters a non-conduction state.

Circuit device, switching regulator, and electronic apparatus for DC to DC conversion

Provided is a circuit device in which reduction of power consumption, reduction of the number of parts, and the like can be realized by eliminating the need for a sense resistor. The circuit device includes a bridge circuit, and a control circuit configured to compare a reference voltage VR and a detection voltage V(V) set using the on-current and the on-resistance of at least one of a low-side transistor and a high-side transistor, output a detection result, control switching on and off of transistors in the bridge circuit, and perform switching from a charge period to a decay period.

A circuit device includes an output circuit having a high-side transistor and a low-side transistor, and a control circuit configured to detect a voltage between the drain node and the source node of a detection target transistor that is at least one of the low-side transistor and the high-side transistor, and detect a malfunction in the case where it is determined that the detection voltage did not exceed a given comparison voltage.

Growing community of inventors

Nagoya, Japan

Atsushi Yamada