Abstract: A solar cell power source device is disclosed which optimizes the power output of the solar cell by detecting a maximum power point of the solar cell and controlling the duty cycle of a switching transistor in a switching power converter such that the output current of the solar cell follows the maximum power point. Also shown is a pulse width modulation controller which multiplies the output voltage of the solar cell by the output current of the solar cell to obtain a power detecting signal, samples the power detecting signal during two different sample periods to determine if the power output is decreasing, and modulating the pulses output to the switching transistor of the switching power converter in order to maintain the power output of the solar cell at the maximum power point.

Abstract: A maximum power point detecting circuit is disclosed including: a power detector for generating a power detecting signal responsive to an output voltage and an output current of a solar cell; a comparator for comparing a previous power average value with a current power average value according to the power detecting signal for a constant time; and a discriminator for latching an output signal of the comparing means immediately after a current constant time, setting an output immediately before a previous constant time, and judging that an output power of the solar cell decreases when the current power average value is smaller than the previous power average value to generate a discriminating signal.

Abstract: A temperature-compensating overcurrent detection circuit for a DC motor comprising a converter, an integrator and an overcurrent detector. The present invention provides for an overcurrent detection circuit for a DC motor that is adapted compensate for operating temperature of the motor's environment and such compensating detection circuit does not respond with an early forcible operation when the mechanical device is constrained. The overcurrent detection circuit is adapted to permit the motor to carry out its intended operation exactly without having malfunctions due to noise and a temporary overcurrent.

Abstract: A power transistor driving circuit for a single power source drives a predetermined load and prevents each of the drive circuit transistors from being damaged because they are not turned on simultaneously.

Abstract: A time-compensated overcurrent detection circuit shuts off a D.C. motor during large overcurrent conditions caused by actual constraints on the motor. The circuit prevents premature motor shut off by establishing a minimum activation time for shutting off the D.C. motor. An overcurrent time compensator establishes a minimum time period for activating a motor reset signal after sensing an overcurrent condition. The circuitry uses a relatively small capacitor that provides quick response to overcurrent conditions.

Abstract: A controller for performing a zero voltage switching using a resonance mode converter, and an electronic ballast adopting the same, includes a power controller, a shutdown protection circuit and a brownout circuit, and performs a switching when voltage of a switching element is zero, thereby preventing excessive power consumption, enhancing efficiency and decreasing noise.

Abstract: The driving apparatus for a power antenna, e.g. an extensible-retractable automotive radio antenna, is provided with stability function which controls the operation of the motor driving the power antenna until the power antenna is varied into a state for performing normal operation, and provides hysteresis to prevent a state of the controlling signal from being varied too often by a voltage drop generated in rotation of the motor.

Abstract: An overcurrent-detecting device for a DC motor includes a converter for changing a current signal to a voltage signal in a motor; an integrator for comparing an input signal from the convertor with a first reference voltage, and for integrating an excessive value of the reference voltage; and a detector for comparing an input signal from the integrator with a second reference voltage, sensing an overcurrent when the input signal is smaller than the second reference voltage, and outputting a resultant signal. In detecting an overcurrent of the DC motor, the device integrates a higher voltage than a reference voltage, and then detects an overcurrent when the DC motor is constrained.

Abstract: A controller for performing a zero voltage switching using a resonance mode converter, and an electronic ballast adopting the same, includes a power controller, a shutdown protection circuit and a brownout circuit, and performs a switching when voltage of a switching element is zero, thereby preventing excessive power consumption, enhancing efficiency and decreasing noise.