Abstract: An imaging apparatus includes a lens unit to be mounted in one-touch on a module unit affixed by reflow soldering or the like to a base plate. When the lens unit is mounted in one-touch on the module unit, the conical outer circumferential surface of a tip-end part of a lens press-fitting part is in close contact with the inner circumferential surface of the conical concave part of the holder to regulate the coaxiality of the installed lens. A flange face of the lens is directly received and supported by the holder to regulate the parallelity with the imaging element and, in addition, when the lens unit is mounted in one-touch on the module unit, the barrel which is integrally formed with the lens press-fitting part is snap-locked onto the upper end part of the holder to ensure the fixing of the barrel.

Abstract: 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 detector 9 for generating a current detection signal Vc corresponding to the current of a rectifier 4; an error amplifier 8 for generating an error signal Ve corresponding to an output DC voltage Vo; and a control circuit 10 for turning ON/OFF the main switch 3 on the basis of the current detection signal Vc and the error signal Ve. The control circuit 10 comprises a comparator 11 and a timer circuit 12. With this configuration, the ON time of the main switch 3 is 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.

Abstract: The present invention is intended to provide a DC-DC converter, in which the relationship between the duty ratio of a drive signal and the output DC voltage is nonlinear, being characterized in that the relationship between an error signal and the output DC voltage is linear, and that the design of stabilizing the feedback system is facilitated. The DC-DC converter comprises an error-amplifier circuit for generating the error signal that is obtained by amplifying the error between the output and a target value, an oscillating circuit for generating a triangular wave signal having an amplitude corresponding to the error signal, and a comparison circuit for comparing the triangular wave signal with a reference signal having a predetermined value and for generating the drive signal to turn ON/OFF a switching device.

Abstract: For downsizing a charge pump circuit which selects a voltage multiple ratio, converts its input voltage and outputs the converted voltage, the number of switching devices of the charge pump circuit is reduced. The control circuit of the charge pump circuit is configured to carry out switching control for multiple switching devices and charge/discharge at least a first capacitor and a second capacitor so as to have at least a 2Vi mode for alternately repeating a first state and a second state, and a 1.5Vi mode for alternately repeating a third state and a fourth state, thereby carrying out boosting depending on the detected input voltage.

Abstract: A step-up converter includes an inductor which receives input voltage Vi at one end, a first FET of the first conduction type which functions as a switch for determining whether or not energy is accumulated in the inductor, a second FET of the second conduction type which rectifies a current output from the other end of the inductor, an output capacitor having an end connected to the source of the second FET, a current detection circuit, and a feedback control circuit. The current detection circuit detects a current flowing through the first N-channel FET to output current detection signal Vc. The feedback control circuit controls the operations of the first N-channel FET and a P-channel FET based on current detection signal Vc.

Abstract: 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 detector 9 for generating a current detection signal Vc corresponding to the current of a rectifier 4; an error amplifier 8 for generating an error signal Ve corresponding to an output DC voltage Vo; and a control circuit 10 for turning ON/OFF the main switch 3 on the basis of the current detection signal Vc and the error signal Ve. The control circuit 10 comprises a comparator 11 and a timer circuit 12. With this configuration, the ON time of the main switch 3 is 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.

Abstract: In a DC-DC converter conforming to the current mode control system, in which the valley value of an inductor current is controlled for output control, a current detection circuit 6 is configured to detect the current flowing from a low-side FET 2 to an inductor 3 using an FET 60, an NPN transistor 61, an NPN transistor 62, a PNP transistor 64, a PNP transistor 65 and a resistor 66, to detect the current flowing from the inductor 3 to the low-side FET 2 using an FET 67, a differential amplifier 68, an FET 69 and the resistor 66, and to output a current detection signal Vc.

Abstract: To provide an imaging apparatus employing a fixed focal length nonadjustable lens, characterized in that a lens unit is configured to be mounted in one-touch on a module unit affixed by reflow soldering or the like to a base plate. An imaging apparatus configured so that, when the lens unit is mounted in one-touch on the module unit, the conical outer circumferential surface of a tip-end part of a lens press-fitting part is in close contact with the inner circumferential surface of the conical concave part of the holder to regulate the coaxiality of the installed lens, and a flange face of the lens is directly received and supported by the holder to regulate the parallelity with the imaging element and, in addition, when the lens unit is mounted in one-touch on the module unit, the barrel which is integrally formed with the lens press-fitting part is snap-locked onto the upper end part of the holder to ensure the fixing of the barrel.

Abstract: For downsizing a charge pump circuit which selects a voltage multiple ratio, converts its input voltage and outputs the converted voltage, the number of switching devices of the charge pump circuit is reduced. The control circuit of the charge pump circuit is configured to carry out switching control for multiple switching devices and charge/discharge at least a first capacitor and a second capacitor so as to have at least a 2Vi mode for alternately repeating a first state and a second state, and a 1.5Vi mode for alternately repeating a third state and a fourth state, thereby carrying out boosting depending on the detected input voltage.

Abstract: An output detection feedback section (5) for controlling the power supply output voltage of a converter unit (4) in response to an error signal Ve has an error amplifier (26) for outputting the error signal Ve, a phase compensation circuit (41), a state detection circuit (42), and a response compensation circuit (43) for setting the voltage of a capacitor (29) of the phase compensation circuit (41) to a predetermined value. When output voltage is switched, the output voltage is fixed at the predetermined value in a DC manner while a transitional response of the error signal (Ve) is accelerated, so that the output voltage is changed at a high speed to a desired value and the overshoot and undershoot are suppressed around the desired value.

Abstract: The present invention is intended to provide a DC-DC converter, in which the relationship between the duty ratio of a drive signal and the output DC voltage is nonlinear, being characterized in that the relationship between an error signal and the output DC voltage is linear, and that the design of stabilizing the feedback system is facilitated. The DC-DC converter comprises an error-amplifier circuit for generating the error signal that is obtained by amplifying the error between the output and a target value, an oscillating circuit for generating a triangular wave signal having an amplitude corresponding to the error signal, and a comparison circuit for comparing the triangular wave signal with a reference signal having a predetermined value and for generating the drive signal to turn ON/OFF a switching device.

Abstract: In a DC-DC converter conforming to the current mode control system, in which the valley value of an inductor current is controlled for output control, a current detection circuit 6 is configured to detect the current flowing from a low-side FET 2 to an inductor 3 using an FET 60, an NPN transistor 61, an NPN transistor 62, a PNP transistor 64, a PNP transistor 65 and a resistor 66, to detect the current flowing from the inductor 3 to the low-side FET 2 using an FET 67, a differential amplifier 68, an FET 69 and the resistor 66, and to output a current detection signal Vc.

Abstract: A step-up converter includes an inductor which receives input voltage Vi at one end, a first FET of the first conduction type which functions as a switch for determining whether or not energy is accumulated in the inductor, a second FET of the second conduction type which rectifies a current output from the other end of the inductor, an output capacitor having an end connected to the source of the second FET, a current detection circuit, and a feedback control circuit. The current detection circuit detects a current flowing through the first N-channel FET to output current detection signal Vc. The feedback control circuit controls the operations of the first N-channel FET and a P-channel FET based on current detection signal Vc.

Abstract: A current detector detects a current flowing through a high-side switch to output a current detection signal. When the current detection signal is lower than an error signal which is generated based on the difference between an output voltage and a reference voltage, a comparator outputs a signal. A timer outputs a signal a predetermined time after the high-side switch is turned ON. When the timer outputs the signal and the comparator outputs the signal, the high-side switch is turned OFF.

Abstract: An output detection feedback section (5) for controlling the power supply output voltage of a converter unit (4) in response to an error signal Ve has an error amplifier (26) for outputting the error signal Ve, a phase compensation circuit (41), a state detection circuit (42), and a response compensation circuit (43) for setting the voltage of a capacitor (29) of the phase compensation circuit (41) to a predetermined value. When output voltage is switched, the output voltage is fixed at the predetermined value in a DC manner while a transitional response of the error signal (Ve) is accelerated, so that the output voltage is changed at a high speed to a desired value and the overshoot and undershoot are suppressed around the desired value.

Abstract: A DC-DC converter has switching means which generates a continuous switching voltage having a specified period from an input voltage and outputs the generated switching voltage, output voltage generating means which receives the switching voltage at an inductor and generates an output voltage obtained by rectifying and smoothing a voltage generated in the inductor, lamp signal generating means which generates a lamp signal and outputs the generated lamp signal, and control means which performs an arithmetic operation using a current signal relative to a current flowing in the inductor, an error signal relative to the output voltage, and the lamp signal to generate a control signal for controlling the operation of the switching means and outputs the generated control signal to the switching means.

Abstract: A multi-output power supply circuit comprising a switching circuit 10 having a series circuit of a high-side switch 11 and a low-side switch 12, connected in parallel with an input DC power supply 1, and a step-down control circuit 13, and multiple step-up circuits 20 and 30 connected to the output terminal of the switching circuit, wherein each step-up circuit has an inductor connected to the output terminal of the switching circuit, a step-up switch, a step-up rectifier, smoothing means for outputting an output DC voltage, and a step-up control circuit for driving the step-up switch.

Abstract: A DC-DC converter has switching means which generates a continuous switching voltage having a specified period from an input voltage and outputs the generated switching voltage, output voltage generating means which receives the switching voltage at an inductor and generates an output voltage obtained by rectifying and smoothing a voltage generated in the inductor, lamp signal generating means which generates a lamp signal and outputs the generated lamp signal, and control means which performs an arithmetic operation using a current signal relative to a current flowing in the inductor, an error signal relative to the output voltage, and the lamp signal to generate a control signal for controlling the operation of the switching means and outputs the generated control signal to the switching means.

Abstract: An LED is provided with a p-type semiconductor region in the shape of an island being buried in an n-type semiconductor region from the surface of it, and forms a pn junction at the interface between these n-type region and p-type region. The pn junction has a bottom junction at the bottom of the n-type region and a side junction at the peripheral side face. The bottom junction comprises a first subjunction being deep and constant in junction depth and a second subjunction varying continuously in junction depth. The depth of the second subjunction is shallower than the depth of the first subjunction. The p-type region portion above the second subjunction is thinner in thickness than the p-type region portion above the first subjunction. A light passing through the p-type region portion of the former is less in absorption and more in optical power of the output light. The total power of the output light of the whole LED is increased correspondingly to reduction in thickness of the p-type region.

Abstract: An LED is provided with a p-type semiconductor region in the shape of an island being buried in an n-type semiconductor region from the surface of it, and forms a pn junction at the interface between these n-type region and p-type region. The pn junction has a bottom junction at the bottom of the n-type region and a side junction at the peripheral side face. The bottom junction comprises a first subjunction being deep and constant in junction depth and a second subjunction varying continuously in junction depth. The depth of the second subjunction is shallower than the depth of the first subjunction. The p-type region portion above the second subjunction is thinner in thickness than the p-type region portion above the first subjunction. A light passing through the p-type region portion of the former is less in absorption and more in optical power of the output light. The total power of the output light of the whole LED is increased correspondingly to reduction in thickness of the p-type region.