Abstract: A light emitting device driving circuit, includes: a switch device, a comparator, a driving module, a time counting circuit and a compensation module. The switch device is turned on or off according to a control signal for controlling a driving current flowing through the light emitting device. The comparator generates a comparison result according to a reference voltage and a feedback voltage corresponding to the driving current. The driving module generates the control signal according to the comparison result. The time counting circuit controls the driving module to turn on the switch device after the switch device turns off for a predetermined time. The compensation module detects a turn on time for the switch device and a delay time between the feedback voltage reaching the reference voltage value and the control signal varying correspondingly, and adjusts the reference voltage according to the turn on time and the delay time.

Abstract: An AC/DC power supply with over-voltage protection includes a voltage converting circuit and a digital latch control circuit. The voltage converting circuit has a first-side winding, a second-side winding, and an auxiliary winding for providing a supply voltage according to the AC input voltage. The digital latch control circuit is coupled to the voltage converting circuit and utilized for latching a voltage level of the supply voltage at a first predetermined level according to an over-voltage protection (OVP) trigger signal, where the voltage converting circuit is disabled when the voltage level is latched at the first predetermined level.

Abstract: A pseudo random clock generator includes a clock generator for generating a clock signal. A pseudo random code generator receives the clock signal and thereby generating a pseudo random code. A code limiter enables the value of the pseudo random code being unchanged for at least two periods of the clock signal. A logic gate applies a logic operation to the pseudo random code and the clock signal and thereby outputting a pseudo random clock.

Abstract: An apparatus is applicable to a power converter comprising a primary winding for receiving an input voltage and a secondary winding for generating an output voltage to power a load. The apparatus comprises a detecting circuit, a comparing circuit, and a determining circuit. The detecting circuit is configured to generate a feedback signal according to the output voltage. The comparing circuit is coupled to the detecting circuit and configured to compare the feedback signal and a threshold and accordingly generates an indication signal indicative of the over high output voltage. The determining circuit, which is in response to the indication signal, is configured to trigger an over voltage protection mechanism preventing the power converter from powering the load. Since the feedback signal is instantly responsive to the output voltage, the occurrence of an error can be rapidly and correctly detected, allowing rapid and correct protection for the power converter.

Abstract: Disclosed is a DC to DC converter, which comprises: a transforming circuit, for transforming an input voltage to an output voltage; a comparator, for comparing a reference voltage and a feedback voltage proportional to the output voltage to generate a comparing signal; a control circuit, coupled to the transforming circuit and the comparator, for controlling the transforming circuit according to the comparing signal; and a time-counting device, coupled to the control circuit, for counting the time of a specific voltage level of the comparing signal; wherein the time-counting device informs the control circuit that a load open situation occurs if the specific voltage level of the comparing signal lasts a predetermined time, then the control circuit turns off the transforming circuit.

Abstract: A pseudo random clock generator includes a clock generator for generating a clock signal. A pseudo random code generator receives the clock signal and thereby generating a pseudo random code. A code limiter enables the value of the pseudo random code being unchanged for at least two periods of the clock signal. A logic gate applies a logic operation to the pseudo random code and the clock signal and thereby outputting a pseudo random clock.

Abstract: Disclosed is a DC to DC converter, which comprises: a transforming circuit, for transforming an input voltage to an output voltage; a comparator, for comparing a reference voltage and a feedback voltage proportional to the output voltage to generate a comparing signal; a control circuit, coupled to the transforming circuit and the comparator, for controlling the transforming circuit according to the comparing signal; and a time-counting device, coupled to the control circuit, for counting the time of a specific voltage level of the comparing signal; wherein the time-counting device informs the control circuit that a load open situation occurs if the specific voltage level of the comparing signal lasts a predetermined time, then the control circuit turns off the transforming circuit.