Abstract: A light-emitting diode (LED) bulb has an LED within a shell. The LED bulb also includes a driver circuit for providing current to the LED. The drive circuit has a thermal protection circuit, which includes a thermistor having a positive thermal coefficient and a switching temperature. The driver circuit also includes a switch-mode power supply (SMPS) controller with an input pin and an output pin. The thermistor is connected to the input pin. When the thermistor temperature is above the switching temperature, the thermal protection circuit causes the SMPS controller to produce a signal with a second duty cycle on the output pin. When the thermistor temperature is below the switching temperature, the thermal protection circuit causes the SMPS controller to produce a signal with a first duty cycle on the output pin. The second duty cycle is higher than the first duty cycle.

Abstract: An over-current protection circuit, including a current input for receiving a input current and a current output electrically connectable to a load, for outputting an output current proportional to the input current. A switch connects the current input to the current output. The switch has at least two switch states including an open state in which a current flow from the current input to the current output is interrupted and a closed state in which the current flow is enabled. The switch includes a switch control input for controlling the switch state. The circuit has a sensor for sensing a load current applied to the load and a controller connected to the sensor for controlling the switch to be in the open state when the sensed load current has exceeded a current threshold during a predetermined period of time, the predetermined period of time being dependent on an amount with which said sensed load current exceeds the threshold.

Abstract: A circuit fault detector and interrupter which consists of parallel current conduction paths, including a path through a mechanical contactor and a path through a power electronics switch having active feedback control. A fault can be detected by a fault detection circuit within 50 ?S of the occurrence of the fault, causing the mechanical contactor to be opened and the fault current to be commutated via a laminated, low-inductance bus through the power electronics switch. The power electronics switch is thereafter turned off as soon as possible, interrupting the fault current and absorbing the inductive energy in the circuit. The fault current can be interrupted within 200 microseconds of the occurrence of the fault, and the device reduces or eliminates arcing when the mechanical contactor is opened.

Abstract: An inrush current higher than a second anomaly threshold current ILfc passes through a power MOSFET 14, when a control signal S1 of low level is applied to a gate driver 28 so that the power MOSFET 14 and the like turn to a conductive state. A first forcing shutoff operation for the power MOSFET 14 is then prevented, because a first anomaly threshold current ILoc is set to an initial level higher than the inrush current. A fuse time counter 73 starts a count-up operation in response to the occurrence of the inrush current, and continues to increment its count value until a load current IL falls below the second anomaly threshold current ILfc. According to the count value, the first anomaly threshold current ILoc is decreased stepwise with time.

Abstract: A safety-related communication system includes a safety relay with signal inputs of an input signal current circuit that connect the safety relay to a control device for monitoring the input signal circuit. The safety relay also includes at least two load outputs of a load current circuit for connecting to a load. Switching elements are connected in parallel and configured to switch the load current circuit on or off based on an activation signal at the input signal current circuit. A diagnostic device monitors faults in the load current circuit and/or the safety relay. A signaling device connected to the signal inputs provides an impedance for the input signal circuit. The impedance is tuned to the control device during a fault-free state and is detunable upon detection of a fault so as to signal the detected fault to the control device via the input signal current circuit.

Abstract: A resistive element which includes an element body that contains, as its main constituent, an oxide conductor represented by RBaMn2O6 (wherein R is at least one selected from among Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Y) and which has a negative temperature coefficient; and a pair of electrodes for applying an electric field to a surface layer section of the element body. When the resistive element is used in, for example, an infrared light sensor, infrared light is detected in such a way that measures an electric current flowing through the element body, which is correlated with the resistance of the element body, when an electric field with an electric field intensity of 100 V/cm or more is applied to the element body.

Abstract: An arrangement having DC power supply units connection parallel, wherein, the power supplies of the DC power supply units each generate a partial output current for supplying a load with a total output current. In accordance with the invention, an overload of power supply units when the power supply units are switched on and/or during their restart is largely avoided.

Abstract: An apparatus protects a battery by comparison of full charge capacity. The apparatus includes a fuse connected on a circuit path along which a charging or discharging current flows, a fuse control switch for selectively opening or closing an operating current applied to the fuse, and a controller for calculating an actual value and a reference value of a full charge capacity of a battery, comparing the actual value with the reference value, and then controlling the fuse control switch according to the comparison result to melt and cut the fuse. Thus, an abnormal state of a battery may be found and controlled at an early stage, so it is possible to prevent any problem such as firing and thus improve the safety of a battery.

Abstract: An overcurrent protection device includes a power input terminal, a power output terminal, a first signal terminal, a second signal terminal, a testing circuit, and a switch element. The power input terminal and the first signal terminal are connected to a power supply. The power output terminal and the second signal terminal are connected to a computer motherboard. If the first and second terminals are disconnected from each other when the computer motherboard works, the power supply stops working. The testing circuit includes a fixed resistor and a control chip parallel connected between the power input and output terminal. The control chip stores a predetermined voltage threshold, and detects voltage between the two terminals of the fixed resistor, and compares the measured voltage with the predetermined voltage threshold. The switch element disconnects the first and second signal terminals when the measured voltage is greater than the predetermined voltage threshold.

Abstract: A power distribution system and method has a controller and at least one semiconductor switch. The power distribution system additionally has an on status detector which detects the status of the semiconductor switches, and an overcurrent status circuit which checks for overcurrent conditions.

Abstract: An over-current protection apparatus includes a first connector connected to a power supply, a second connector connected to a motherboard. A non-inverting input terminal of a comparator receives a voltage from a power supply and compares the received voltage with a preset voltage, when the received voltage is greater than the preset voltage. The comparator outputs a high level signal to control a first electrical switch to be turned on and a second electrical switch to be turned off. A clock pin of a flip-flop receives a high level signal from the second electrical switch, and an output terminal of the flip-flop outputs a low level signal to a third electrical switch, to control the third electrical switch to be turned off. A control pin of a first connector is disconnected to a control pin of a second connector and the power supply does not provide voltages to a motherboard.

Abstract: In an embodiment, a drive circuit for a transistor includes an output for providing a drive signal to the transistor. The drive circuit monitors the transistor for an occurrence of an overload, changes into an overload protection state in which the drive circuit drives the transistor in an ON state upon detection of the overload of the transistor. The drive circuit further changes into a voltage limiting state in which a voltage of the transistor is limited.

Abstract: A power circuit includes a memory power circuit and a central processing unit (CPU) power circuit. The memory power circuit includes a first operational amplifier and a first switch. The CPU power circuit includes a second operational amplifier and a second switch. The memory power circuit supplies power to a memory slot. The CPU power circuit supplies power to a CPU.

Abstract: In a semiconductor device, low-level signals are output from a terminal voltage detecting circuit when the connection between an external terminal and a resistor is cut off, or when the connection between the resistor and a ground voltage is cut off, or when the external terminal short-circuits to the ground voltage. Accordingly, a PMOS transistor is turned on so that an oscillating circuit stops oscillating and outputs high-level signals from its output terminal.

Abstract: A constant voltage power supply circuit includes an output voltage dependent over-current protection circuit unit and a drooping over-current protection circuit unit. The output voltage dependent over-current protection circuit unit reduces, when an output current which is output from an output terminal of an output control transistor exceeds a first set value which is determined in advance, the output current from the first set value in a manner dependent on a reduction of an output voltage which is output from the output terminal. The drooping over-current protection circuit unit detects, with an external resistor, the output current which is output from the output terminal of the output control transistor, and reduces, when the detected output current exceeds a second set value which is determined in advance and which has a lower value than the first set value, the output voltage while maintaining the output current at the second set value.

Abstract: A voltage switching circuit for a secondary battery protection circuit in a battery pack having a negative power supply terminal and a current-detection resistor. The secondary battery protection circuit has a charger negative power supply terminal and a detection circuit. The voltage switching circuit has a first input terminal to which a voltage obtained by converting a current flowing through the current detection resistor is supplied, a second input terminal to which voltages at the negative power supply terminal and at the charger negative power supply terminal are supplied, an output terminal, and a selection terminal. The voltage switching circuit causes an output voltage to switch between the voltages from the first input terminal and the second input terminal according to selection at the selection terminal when an excess current is detected and when the battery pack returns to a chargeable-dischargeable state from a charge-discharge inhibit state.

Abstract: A load driving circuit (20) according to the present invention, for carrying out PWM control to cause currents of respective light emitting diode lines (3-1 . . . 3-N) connected in parallel, each of the light emitting diode lines (3-1 . . . 3-N) including a plurality of light emitting diodes (4) connected in series, causes timing at which a current of any one of the light emitting diode lines (3-1 . . . 3-N) is turned on or off to be different from timing at which current(s) of at least another one of the light emitting diode lines (3-1 . . . 3-N) is(are) turned on or off. This makes it possible to provide a load driving circuit which (i) does not have a reduction in a degree of freedom in selecting a frequency of a PWM control signal that is used to control loads, (ii) does not prevent a peripheral circuit from following the PWM control circuit, and (iii) prevents generation of sounds.

Abstract: A memristor-protection integrated circuit. The memristor-protection integrated circuit includes a first current-bias circuit, a second current-bias circuit, an inverter, and a current limiter. The first and second current-bias circuits are configured to be coupled to first and second power-supply rails, respectively. The inverter is coupled to the first current-bias circuit and to the second current-bias circuit, and is configured to couple at least one memristor to at least one of the first current-bias circuit and the second current-bias circuit in response to an input signal applied to the inverter. The current limiter is coupled to the first current-bias circuit and coupled to the second current-bias circuit, and is configured to limit current flowing through the memristor.

Abstract: Protection unit for an AC or DC low-voltage power supply line, comprising means for detecting the current circulating in one or more power supply line conductor(s) and at least first electronic protection means operatively coupled to a circuit breaker with at least one pole for inserting along said conductor, characterized in that said detection means comprise at least one resistor suitable for electrical connection in series with said circuit breaker pole and for enabling the passage of the current circulating in said conductor, and at least a first electronic processing circuit that receives a signal indicative of the voltage at the terminals of said resistor and delivers to said first electronic protection means a signal that is indicative of the current circulating in said line conductor.

Abstract: Electronic circuit breakers and systems for isolating a load from a power-supply unit are provided. One electronic circuit breaker includes a current sensor, a switching element coupled to the current sensor, and a switch controller coupled to the current sensor and the switching element. The switch controller is powered by the power-supply unit and is configured to switch OFF the switching element when the current sensor detects an amount of current from the power-supply unit greater than a predetermined amount. An electronic system includes a power-supply unit, a load, and the above-referenced electronic circuit breaker coupled to the power-supply unit and the load.

Abstract: Certain example embodiments disclosed herein include an adaptive current limiter comprising a variable reference voltage generator which is coupled to a power source via two input nodes and which develops a voltage step with exponential decay in response to, for example, a transient over-voltage condition, with the output of the variable reference voltage generator supplying a reference voltage to a comparator which compares the reference voltage to a voltage derived from a sensing resistor and, upon detecting an over-voltage condition, signals to a circuit breaker that the circuit should be broken or modified.

Abstract: A short detection circuit, for detecting an output node corresponding to an output voltage converted from an input voltage of a power converter, includes a first current source, a charging/discharging unit, a comparator, and a logic control unit. The charging/discharging unit performs charging operation in accordance with the first current source to generate a charging signal in a shorted condition of the output node. The comparator outputs an enable signal by comparing the charging signal with a reference signal. The logic control unit is controlled by the enable signal to generate a fault signal for turning off a first switch coupled between the output node and the input voltage in the shorted condition of the output node. A method for detecting short of an output node corresponding to an output voltage converted from an input voltage of a power converter is also disclosed herein.

Abstract: A programmable fuse and fuse panel are described. Unlike conventional fuses and fuse panels, the trip values of the fuses of the panel—i.e., the current values at which the fuse trips—are field programmable. One of many advantages includes the ability to adaptively set the trip value of a fuse—depending on the operating needs of a load device—without having to physically exchange the fuse. In an embodiment, electronic fuses are used.

Abstract: An electronic fuse system includes plural current paths, each operable to be coupled between a power source and a load, and each including a switching element and a current sensing resistor in series with the path such that the path passes current when the switching element is turned on and does not pass current when the switching element is turned off. A controller has two sense inputs and a control output. The control output is coupled to the switching elements in each of the plural current paths and is operable to turn them all on or off simultaneously responsive at least in part to the sense inputs. A summing resistor is connected across the two sense inputs, and coupling circuitry is operable to couple voltages appearing across the current sensing resistors to the summing resistor.

Abstract: A semiconductor device with an over-current detection feature is disclosed. According to an example of the invention the device includes: a semiconductor chip including a load current path that conducts a load current in response to an input signal activating the load current flow. A current sensor arrangement provides a measurement signal representing the load current. An evaluation circuit is configured to compare the measurement signal with a first threshold and to signal an over-current when the measurement signal exceeds the first threshold after a delay time period starting from the activation of the load current flow has elapsed.

Abstract: An overcurrent protection circuit includes an operational amplifier, a first resistor, a second resistor, and a switch. A non-inverting input of the operational amplifier is connected to an output of a power supply circuit and an inverting input of the operational amplifier is connected to a first terminal of a load of the power supply circuit. A second terminal of the load is grounded. The first and second resistors are connected in parallel and coupled between the inverting input and the non-inverting input of the operational amplifier. The switch is coupled to an enable terminal of the power supply circuit and coupled to an output of the operational amplifier.

Abstract: An apparatus for protecting a battery pack includes a fuse and a sense resistor, connected on a circuit path along which a charging or discharging current flows, and a fuse control switch for controlling the fuse. Also, the apparatus further includes a Schottky diode having one end connected to the sense resistor and the other end connected to the fuse control switch. Thus, destruction of a sense resistor serving an important role in the battery pack protecting apparatus is detected to melt and cut the fuse, thereby preventing any element from being damaged due to overcurrent and thus improving the safety of a battery pack at a low cost.

Abstract: A communication system comprises a twisted pair communication link operably coupled to at least two driver stages for providing at least two independent input signals on the twisted pair communication link. The at least two independent input signals on the twisted pair communication link are summed and input to a comparator arranged to compare the summed signal to a reference value. The output of the comparator is input to the at least two driver stages. The outputs from the at least two driver stages are summed and fed back and summed with one or more of the independent input signals. In this manner, adverse effects due to non-ideal symmetry between components in a twisted pair communication link, such as a Controller Area Network system, are reduced.

Abstract: The present invention provides a control apparatus for detecting an early stage short circuit between the terminals of an electrolytic capacitor, and detecting a short circuit between a load that is connected in parallel to the electrolytic capacitor, the apparatus performing appropriate processing before an adverse effect is inflicted on peripheral equipment. In the control apparatus, microcomputers switch on a second relay; an electrolytic capacitor is gradually charged via a current-limiting resistor; a first voltage detection control for detecting a voltage between terminals of the electrolytic capacitor is performed when a first set time period has elapsed after the second relay has been switched on; and a second voltage detection control for detecting a voltage between the terminals of the electrolytic capacitor is performed when a second set time period, which is longer than the first set time period, has elapsed after the second relay has been switched on.

Abstract: A power supply apparatus comprises a current limiting unit connected in series between a power source and a power supply circuit that limits output current of the power source; a first switch connected in series with the current limiting unit; a second switch connected in parallel with the current limiting unit; a resistor connected in series between the power source and the current limiting unit; an abnormal current detection unit, connected in parallel with the resistor, that detects the current flowing through the resistor and determines whether or not the detected current is abnormal; and a control unit that turns on the first switch if the abnormal current detection unit detects a current, and, thereafter, turns the second switch on if the detected current is not abnormal, and turns the first switch off if the detected current is abnormal.

Abstract: An overcurrent protection circuit includes a current limiter and a status detector, and a voltage regulator includes an output transistor. The output transistor is configured to regulate a voltage input to an input terminal to output a given constant voltage from an output terminal, while passing a current from the input terminal to the output terminal according to a control signal applied thereto. The current limiter reduces the current passed through the output transistor when the passed current exceeds a given current limit. The status detector is configured to generate a status signal indicating operation of the current limiter. A constant voltage regulator incorporating the overcurrent protection circuit is also disclosed.

Abstract: A protection circuit is installed between a gate terminal (a control terminal) and an emitter terminal (a ground terminal) of a voltage driven element generally called a power device. The protection circuit is structured as a duplex protection system in which a first discharge circuit is configured to perform a discharge from the control terminal at a current value set in accordance with a current flowing between the load terminal and the ground terminal, an overcurrent generation detection device is configured to detect an existence of an overcurrent between the load terminal and the ground terminal, and a second discharge circuit is configured to perform the discharge from the control terminal at a predetermined constant current value after the overcurrent is detected.

Abstract: Devices, such as mobile devices, may be exposed to short circuit and output overload events. To protect against such events, mobile devices typically include current limit circuits. Some current limit circuits may involve user programmable function. User programmable function may need accurate current limit detectors. Various embodiments of the present invention include devices and methods for detecting one or more programmed current limits. Some embodiments allow for a user application to select among parallel or serial configurations of current detection circuitry. Each such configuration may include multiple resistive devices of different resistive values.

Abstract: In one embodiment the present invention includes an over-current protection method. The method comprises generating a switching signal, starting and stopping a timer, sensing a current through a switch, comparing a response time to a reference time, and generating an over-current alarm signal. The switching signal activates one or more switches in a switching regulator. The timer is started in response to the switch being activated and is stopped in response to the sensed current exceeding a threshold. The response time indicates the time period between the starting and the stopping of the timer. The over-current alarm signal is generated if the response time is less than the reference time.

Abstract: A safety device for a semiconductor switch controlling a secondary line provided with a fuse on the input side of the switch device that includes component to create a short circuit in the secondary line, so as to cut off the fuse, and means of activating this component following detection of an overcurrent in the secondary line.

Abstract: An electric control and protection system for an output channel of automation equipment, the output channel being capable of controlling an electrical load as a function of a control signal from the automation equipment, the control and protection system including: a device that switches the electrical load including an MOS switching transistor, a source of the MOS switching transistor being connected to a positive voltage terminal via a resistor and a drain of the MOS switching transistor being connected to the electrical load, the MOS switching transistor being switchable between an on-state in which the electrical load is connected to the resistor and an off-state.

Abstract: An over-current protection circuit for use with a constant voltage circuit that converts an input voltage to a predetermined output voltage and that outputs the predetermined output voltage.

Abstract: A power supply control system having a first switch circuit configured to set a power supply line which connects a power supply unit and a power supply circuit to one of a connected state and a non-connected state, a first control unit configured to operate in one of a normal mode and a sleep mode in which a consumption current is smaller than in the normal mode, and to detect a magnitude of a current flowing into the first switch circuit and control an operation of the first switch circuit based on the detected magnitude of the current while operating in the normal mode, and a second control unit configured to control an operation of the first control unit based on the detection result of an opening-closing state detection unit configured to detect an opening-closing state of a battery lid provided to the power supply unit.

Abstract: A switching element driving device has a first transistor that decreases the gate voltage of a power element at a faster rate than during a normal turn-off, and a second transistor that decreases the gate voltage of the power element at a slower rate than during a normal turn-off. If the gate voltage detected by the gate voltage monitoring means when an overcurrent in the power element is detected by overcurrent detection means is greater than a predetermined value, the gate voltage is decreased by the first transistor, and then, while the power element remains on, the gate voltage is decreased by the second transistor. If the gate voltage detected by the gate voltage monitoring means when an overcurrent in the power element is detected by overcurrent detection means is less than or equal to the predetermined value, the gate voltage is decreased only by the second transistor.

Abstract: An overcurrent protection apparatus for a load circuit can detect an overcurrent with a high accuracy without being influenced by a deviation ±?Ron of the on-resistance of a semiconductor element (T1). Supposing that a ratio (R3/R1) between a resistor R3 and a resistor R1 is an amplification factor m, a determination voltage generated by resistors R4, R5 is V4 and the average value of the on-resistance of a MOSFET (T1) is Ron, the overcurrent protection apparatus for a load circuit controls either a current I3 flowing through the resistor R3 or a current IR5 flowing through the resister R5 so that the output signal of a compactor CMP1 is inverted when a current having a value of (V4/m/Ron) flows into the MOSFET (T1).

Abstract: A low power solenoid control circuit including a power source in series with a sensing element and a first diode, an inductor to actuate a valve, an energy storage device to store and discharge energy into the inductor, diodes to control current flow, and switches and a controller to control the circuit. The circuit may be operated by closing a first switch, thereby allowing a source current to flow through an inductor; opening the first switch, thereby forcing a charge current to flow through an energy storage device utilizing the inductance of the inductor; repeating these steps until the energy storage device is sufficiently charged; and upon command, closing a second switch, thereby forcing a discharge current to flow from the energy storage device to the inductor causing the inductor to produce an actuating magnetic field thereby actuating a mechanical valve.

Abstract: Apparatus for testing an opto-switch includes a first sense resistor coupled between a power source and an input of the opto-switch, and a second sense resistor coupled to an output of the opto-switch. A test circuit is coupled to sense a first current flowing through the first sense resistor and a second current flowing through the second sense resistor and to generate a test signal responsively to a relation between the first and second currents. A controller is coupled to receive the test signal and to perform a protective action when the test signal exceeds a predetermined limit.

Abstract: A power supply providing current interruption based on the energy from the supply over a sliding window of time is disclosed. The output current from the supply is periodically reestablished.

Abstract: A system and method of classifying a high powered device (PD) with an increased current limit includes: connecting a voltage to the PD, measuring current through a classification resistor connected to the PD, and determining a PD classification signature based on the current according to classification steps such that a minimum classification step includes a minimum current of 0 mA and a maximum classification step includes a maximum current beyond a predetermined current limit. The system includes a PSE, voltage source, PD classification resistor, and PD voltage, connected to the P. An alternative embodiment further includes a discrete classification circuit and discrete classification resistor to be used to measure the current for classification purposes instead of the PD classification resistor when the PD and PD classification resistor do not support power classification under the classification scheme.

Abstract: A power supply apparatus comprises a current limiting unit connected in series between a power source and a power supply circuit that limits output current of the power source; a first switch connected in series with the current limiting unit; a second switch connected in parallel with the current limiting unit; a resistor connected in series between the power source and the current limiting unit; an abnormal current detection unit, connected in parallel with the resistor, that detects the current flowing through the resistor and determines whether or not the detected current is abnormal; and a control unit that turns on the first switch if the abnormal current detection unit detects a current, and, thereafter, turns the second switch on if the detected current is not abnormal, and turns the first switch off if the detected current is abnormal.

Abstract: Methods and apparatus to provide power distribution switch circuits with fast responses to hard short-circuits are disclosed. In one example, a power distribution switch to detect a hard short-circuit condition is described, comprising a switching device having a resistance between an input terminal and an output terminal, to conduct a current from an input power source having an input voltage to an output terminal having an output voltage, a voltage feedback loop having a digital output voltage to increase the resistance of the switching device in response to a short-circuit based on the output voltage, and an analog current feedback loop to increase the resistance of the switching device based on a current through the switching device and a reference current.

Abstract: An in-rush current limiting circuit is disclosed. An apparatus according to aspects of the present invention includes a power switch having a first, second and third terminals. A capacitor having a first terminal and a second terminal is also included. The second terminal of the capacitor is coupled to the first terminal of a current source. The second terminal of the current source is coupled to a second input terminal of the in-rush current limit circuit. A power switch is also included. The first terminal of the power switch is coupled to the anode of a diode. The cathode of the diode is connected to the first terminal of the current source. The second terminal of the power switch is coupled to a second input terminal of the in-rush current limit circuit. The third terminal of the power switch is coupled to be responsive to a voltage across the current source circuit in response to a rate of change of voltage between first and second terminals of the power switch.

Abstract: A second forcing shutoff operation is performed for a power MOSFET 15 and the like, if a time when a load current (or a sense current Is) passing on a power supply line L exceeds a first threshold current Ia reaches a first reference time. On the other hand, the count value of a fuse time counter 71 is cleared to be “zero” so that the shutoff operation for the power MOSFET 15 and the like is not performed, if a normal state, in which neither an overcurrent nor a fuse current has occurred, continues for a second reference time without the first reference time being reached.

Abstract: An error detection apparatus for detecting an error in a power signal output by an external device switchable by a switching signal has a comparing unit for comparing the power signal with a reference signal to yield a comparison signal, a switching unit for providing the switching signal dependent on a control signal with the switching unit being designed to disregard the control signal and to ensure that the external device is switched off upon provision of a triggering signal to the switching unit, and a triggering unit for providing the triggering signal depending on the control signal and the comparison signal. Alternatively, the error detection apparatus has an influencing unit for influencing the power signal, such that the power signal fulfils a predetermined relationship to a reference signal in the case of an occurrence of the error, whereas the relationship is not fulfilled in the absence of the error.

Abstract: The present invention provides a power supply control system comprising a first switch circuit configured to set a power supply line which connects a power supply unit and a power supply circuit to one of a connected state and a non-connected state, a first control unit configured to operate in one of a normal mode and a sleep mode in which a consumption current is smaller than in the normal mode, and to detect a magnitude of a current flowing into the first switch circuit and control an operation of the first switch circuit based on the detected magnitude of the current while operating in the normal mode, and a second control unit configured to control an operation of the first control unit based on the detection result of an opening-closing state detection unit configured to detect an opening-closing state of a battery lid provided to the power supply unit.