Abstract:
A control device of a switching converter controls the closing and opening of a switch of the converter that regulates the operation of an inductor. The control device includes a ramp voltage generator, a switch control circuit configured to close the switch based on a comparison of the ramp voltage with a first signal and a generator control circuit configured to control the ramp voltage generator based on a value of a second signal representative of a current flowing through the inductor of the converter, in comparison with the value of a third signal.
Abstract:
A control device for a transistor of a switching converter rectifier generates a control signal of the transistor and includes a circuit to measure the conduction time of the body diode of the transistor cycle by cycle. When the conduction time is greater than a first threshold, the off time instant of the transistor is delayed by a first quantity in the next cycles, until the conduction time is less than the first threshold and greater than a second threshold. When the conduction time is between the first and second thresholds, the off time instant is delayed by a fixed second quantity in the next cycles until the conduction time is lower than the second threshold, with the second quantity less than the first quantity. When the conduction time is lower than the second threshold, the off time instant is advanced by the second quantity in the next cycle.
Abstract:
A control device controls a switching converter. The converter has an input alternating supply voltage, a regulated direct voltage on the output terminal, and a switch connected to an inductor. The control device controls the closing and opening time period of said switch for each cycle and receives a first input signal representative of the current flowing through one element of the converter. The control device comprises a counter configured to count a time period, a comparator configured to compare said first input signal with a second signal, digital control block configured to control the closing and opening of said switch and to activate said counter to start the counting of said time period when the said first input signal crosses said second signal, with said switch being closed. The digital control block is configured to open the switch when the counter finishes the counting of said time period.
Abstract:
A control device controls a switching converter. The converter has an input alternating supply voltage, a regulated direct voltage on the output terminal, and a switch connected to an inductor. The control device controls the closing and opening time period of said switch for each cycle and receives a first input signal representative of the current flowing through one element of the converter. The control device comprises a counter configured to count a time period, a comparator configured to compare said first input signal with a second signal, digital control block configured to control the closing and opening of said switch and to activate said counter to start the counting of said time period when the said first input signal crosses said second signal, with said switch being closed. The digital control block is configured to open the switch when the counter finishes the counting of said time period.
Abstract:
A control device for a transistor of a switching converter rectifier generates a control signal of the transistor and comprises a circuit to measure the conduction time of the body diode of the transistor cycle by cycle. When the conduction time is greater than a first threshold, the off time instant of the transistor is delayed by a first quantity in the next cycles, until the conduction time is less than the first threshold and greater than a second threshold. When the conduction time is between the first and second thresholds, the off time instant is delayed by a fixed second quantity in the next cycles until the conduction time is lower than the second threshold, with the second quantity less than the first quantity. When the conduction time is lower than the second threshold, the off time instant is advanced by the second quantity in the next cycle.
Abstract:
A control device of a switching converter controls the closing and opening of a switch of the converter that regulates the operation of an inductor. The control device includes a ramp voltage generator, a switch control circuit configured to close the switch based on a comparison of the ramp voltage with a first signal and a generator control circuit configured to control the ramp voltage generator based on a value of a second signal representative of a current flowing through the inductor of the converter, in comparison with the value of a third signal.
Abstract:
A control device detects zero crossings of a current through a rectifier transistor during plural cycles; generates a turn-on signal of the transistor and inserts a turn-on delay equal to a fixed first quantity from the start time of for each cycle. The control device starts counting consecutive cycles after inserting the turn-on delay; detects whether a zero crossing of the current through the transistor after turning on said transistor has occurred; if no zero crossing is detected before counting a number N of consecutive cycles, decreases the turn-on delay by a fixed second quantity for the next cycle; if a zero crossing is detected, maintains turned on the transistor; if the turn-on delay is smaller than first quantity, increases the turn-on delay o for the next switching cycle; and if the turn-on delay is equal to the first quantity, maintains the turn-on delay for the next switching cycle.
Abstract:
A transition mode power factor correction converter comprising a boost inductor, a switch, a diode, and output tank capacitor, has circuit means of limitation of the off-time interval of the switch to a fraction of the off-time interval, “complementary” to the on-time interval that is normally controlled for regulating the output voltage, during part of a cycle of a rectified sinusoidal voltage waveform input to the converter, when the current flowing in the inductor reaches a maximum threshold, causing the mode of operation of the device to switch from transition mode to continuous current mode for a middle phase angle region of a rectified sinusoidal input voltage waveform, under high load conditions, defined by said maximum current threshold. Current peaks amplitude and ripple are effectively reduced for same output power.
Abstract:
A transition mode power factor correction converter comprising a boost inductor, a switch, a diode, and output tank capacitor, has circuit means of limitation of the off-time interval of the switch to a fraction of the off-time interval, “complementary” to the on-time interval that is normally controlled for regulating the output voltage, during part of a cycle of a rectified sinusoidal voltage waveform input to the converter, when the current flowing in the inductor reaches a maximum threshold, causing the mode of operation of the device to switch from transition mode to continuous current mode for a middle phase angle region of a rectified sinusoidal input voltage waveform, under high load conditions, defined by said maximum current threshold. Current peaks amplitude and ripple are effectively reduced for same output power.
Abstract:
A control circuit for a switching voltage regulator is configured to receive an error signal representative of a regulator output voltage in relation to a nominal output voltage, and includes a set/reset flip-flop, a hysteresis comparator and a logic circuit. The flip-flop is configured to produce a switching control signal according to logic values at its set and reset terminals. The comparator is configured to produce a set signal at the set terminal when an error signal drops below a first value, and a reset signal when the error signal rises above a second value. The logic circuit is configured to prevent transmission of the reset signal to the reset terminal during a selected minimum time period and to thereafter enable transmission of the reset signal, and further, to produce an alternate reset signal at the reset terminal at the end of the selected maximum time period.