Abstract: A temperature protection circuit comprises means adapted to compare the temperature being monitored with each of threshold temperatures and judging that the temperature being monitored reaches a threshold temperature when the temperature being monitored is maintained at the threshold temperature or more for a predetermined confirmation period, means adapted to set a longer confirmation period as the threshold temperature compared with the temperature being monitored is lower, means adapted to generate one of corresponding temperature protection signals (Sarm, Slmt, Stsd1, Stsd2) according to the judgment of which threshold temperature the temperature being monitored reaches. With this constitution, temperature protection operation can be preformed with high accuracy and high safety without unnecessarily narrowing the range of the operating temperature of an IC to be protected.

Abstract: An overcurrent detection circuit that detects an overcurrent state of a transistor that outputs a current to a load is provided with a start-up monitoring portion that distinguishes between a start-up state and a steady state, an overcurrent monitoring portion that monitors an overcurrent state of the transistor, and an output voltage monitoring portion that detects whether the output voltage to the load is normal or abnormal. The overcurrent monitoring portion changes an overcurrent detection level while referring to information from the start-up monitoring portion and the overcurrent monitoring portion.

Abstract: An IC includes an internal circuit that switches between on-state and off-state in response to an external signal and also includes an oscillator circuit that is externally synchronized. The IC further includes a state holding circuit that, when pulses for synchronizing the oscillator circuit are inputted to a standby pulse input terminal, applies, to the internal and the oscillator circuits, as an operation signal, a voltage obtained by rectifying pulses outputted from a comparator, and, when a constant voltage for non-operation is applied to the standby pulse input terminal for a given time period, applies, to the internal and oscillator circuits, as a non-operation signal, a constant voltage outputted from the comparator.

Abstract: A switching regulator type power supply apparatus that converts an input voltage and then feeds the voltage thus converted to a smoothing circuit, and that operates in such a way that an output from the smoothing circuit becomes equal to a predetermined output voltage includes a control circuit for generating a control signal by a PWM scheme so that the output becomes equal to the predetermined output voltage, and a switching element that is switched by the control signal so as to convert the input voltage and feed the voltage thus converted to the smoothing circuit. Here, based on an external signal for turning on/off an output of the output voltage, a supply path for supplying an operating power to elements constituting the control circuit is switched between a conducting state and a non-conducting state.

Abstract: An excess current detecting circuit detects an excess current status of a power MOS transistor, which outputs a current to a load from a drain electrode, and outputs the excess current detection signal. The excess current detecting circuit is provided with: a detection MOS transistor wherein a source electrode and a gate electrode are connected to a source electrode and a gate electrode of the power MOS transistor, respectively, a constant current circuit connected with a drain electrode of the detection MOS transistor for flowing a prescribed constant current to the detection MOS transistor, and a comparator for outputting the excess current detection signal based on the results of the comparison between a potential of the drain electrode of the power MOS transistor and a potential of the drain electrode of the detection MOS transistor.

Abstract: An overcurrent detection circuit (35) that detects an overcurrent state of a transistor (2) that outputs a current to a load (25) is provided with a start-up monitoring portion (31) that distinguishes between a start-up state and a steady state, an overcurrent monitoring portion (33) that monitors an overcurrent state of the transistor (2), and an output voltage monitoring portion (34) that detects whether the output voltage to the load (25) is normal or abnormal. The overcurrent monitoring portion (31) changes an overcurrent detection level while referring to information from the start-up monitoring portion (31) and the overcurrent monitoring portion (33).

Abstract: Provided is a semiconductor integrated circuit device having an output portion that outputs via a switch element a predetermined voltage to the outside from a voltage output terminal through a voltage output line and a control portion that performs predetermined control based on a control signal inputted from outside to a signal input line or a signal input terminal that is so arranged as to be adjacent to a voltage output line or a voltage output terminal. To achieve a highly-reliable semiconductor integrated circuit device that is prevented from being broken even when the voltage output terminal and a terminal adjacent thereto are short-circuited, there is provided a voltage detection portion that detects that a voltage higher than a reference voltage is inputted to the signal input line or the signal input terminal and feeds the resultant signal to the output portion as a voltage detection signal, and the output portion opens the switch element when the voltage detection signal is provided thereto.

Abstract: A battery charger outputs a high voltage even when a power supply device having a rechargeable battery is not connected to the battery charger so that the battery charger can supply the high voltage to the power supply device whenever the power supply device is connected to the output terminal of the battery charger. This battery charger has periodic signal producing means for supplying a periodically varying periodic signal to the output terminal by charging and discharging a capacitor connected to the output terminal, and detecting means for checking whether the power supply device is connected to the battery charger or not by checking through a filter whether the periodic signal is present at the output terminal or not. Thus, although the battery charger has no mechanical switch, it can detect the presence of the power supply device.

Abstract: An IC having a built-in over voltage protecting circuit comprising: a first operating circuit having a first resistor connected to a terminal the voltage at which varies depending on a voltage at a first terminal; a second operating circuit; a protecting circuit having a second resistor, which receives a detection signal via the second resistor and controls the operation of the second operating circuit therewith to thereby protect the operation of the second operating circuit, wherein the first resistor and the second resistor are formed adjacently in a device-isolated common resistor forming land as regions having different conductivity type from that of the resistor forming land, the potential of the resistor forming land is set at a predetermined voltage which is different from the voltage at the first terminal, and the detection signal is generated, when a transistor which is composed by the first resistor, the second resistor and the resistor forming land is turned ON in response to a variation of the vo