摘要:
A switched mode power supply comprises a switched mode converter (12) and a controller for controlling the switched mode converter, wherein the switched mode converter is provided for converting an input voltage (Vin) to an output voltage (Vout) and includes, on a primary side, a primary winding (X1) and a controllable switch based circuitry (31) connecting the input voltage over the primary winding; and, on a secondary side, a secondary winding (X2) coupled to the primary winding, and a capacitive element (C) connected over the secondary winding, wherein the output voltage is obtained as the voltage over the capacitive element. The primary winding comprises a first winding portion (np1) and at least one further winding portion (np2); and the switch based circuitry comprises controllable switches (Q11, Q41, Q12, Q42, Q21, Q31) capable of switching between a first operation state wherein the input voltage is connected only over the first winding portion and at least a second operation state wherein the input voltage is connected over the first and the at least one further winding portions, thereby enabling switching between two different transformer ratios (n1, n2).
摘要:
A control circuit for a switched mode power supply and a related method are provided for controlling switching elements in a power train of a switched mode power supply. The control circuit comprises a mode controller to monitor the output current to determine whether the output current exceeds a current threshold. The mode controller controls the switching controller to generate the switch control signals. When the current exceeds the current threshold, the power train operates in a continuous conduction mode, and when the output current has fallen to or below the current threshold, the operation of the power train is changed from the continuous conduction mode to a pulse skipping mode. The pulse skipping mode is entered from the continuous conduction mode and involves determining the amount of energy stored in a secondary circuit of the power train.
摘要:
A switched mode power supply (SMPS) comprising a controller configured to control switching of the SMPS to regulate an output voltage at an output of the SMPS based on a feedback signal that indicates the output voltage, and a voltage droop control circuit. The voltage droop control circuit comprises a voltage droop control signal generator that detects a voltage drop across a component of the SMPS that is indicative of a current flowing through the output of the SMPS during operation. The voltage droop control signal generator is an active device arranged to generate, based on the detected voltage drop, an output voltage droop control signal for causing the controller to adjust the regulation of the output voltage. The voltage droop control circuit further comprises a reference voltage generator arranged to bias at least one of the first and second inputs of the voltage droop control signal generator.
摘要:
A switched mode power supply (SMPS) is disclosed in which a simple primary side controller is used to send a single pulse of energy to the secondary side to switch on an output voltage controller. The pulse is sent across the main power train and a filtering arrangement is provided on the secondary side to minimise the energy at the output of the SMPS while maximising the energy supplied to the output voltage controller. Advantageously, the SMPS is configured such that the maximum amount of energy transferred from the primary side to the secondary side during a start-up operation is inherently limited. Protection against short circuit conditions and malfunctions is therefore provided without requiring complicated circuitry.
摘要:
An isolated fly-buck converter is provided for converting an input voltage to an output voltage, and for generating a voltage indicative of the input voltage. The isolated fly-buck converter comprises on its secondary side an input voltage sensing circuit for generating the voltage indicative of the input voltage, the input voltage sensing circuit comprising a capacitive element and a rectifying element connected in series. The input voltage sensing circuit is connected across a secondary winding of the isolated fly-buck converter such that the rectifying element prevents current from flowing through the input voltage sensing circuit during the fly-buck phase of operation of the converter. The input voltage sensing circuit also has a voltage buffer arranged to buffer a voltage which is indicative of a sum of the output voltage of the converter and the voltage over the capacitive element, and output the buffered voltage or a voltage based on the buffered voltage as the voltage that is indicative of the input voltage. The output of the voltage buffer is connected to ground via a first resistive element in series with a parallel combination of a second resistive element and a third capacitive element.
摘要:
There is provided a controller for controlling an output current of a switched mode power supply, SMPS. The controller comprises a sampling module arranged to sample a signal indicative of the output current of the SMPS at a frequency higher than a switching frequency of the SMPS, and a filter module arranged to filter out a ripple component of the sampled signal. The filter module comprises: a ripple component estimation module arranged to estimate the ripple component; a moving average calculation module arranged to calculate a moving average of the sampled signal; and a subtraction module arranged to generate a filtered signal by subtracting the estimated ripple component from the sampled signal and the calculated moving average. The controller also has a switching control module arranged to generate a control signal for controlling at least one of the switching frequency and a switching duty cycle of the SMPS based on the filtered signal.
摘要:
An isolated fly-buck converter provided for converting an input voltage (Vin) to an output voltage (VS) comprises (i) on a primary side, a primary winding (X1) and a non-isolated buck (CP) connected in series, and a pair of switches (Q1, Q2), wherein the switches are switchable between a forward phase, in which the primary winding and the non-isolated buck are connected to the input voltage, and a fly-buck phase, in which the primary winding and the non-isolated buck are disconnected from the input voltage and are connected to one another in a closed circuit; and (ii) on a secondary side, a secondary winding (X2) coupled to the primary winding, and a first capacitive element (CS) connected over the secondary winding and a first rectifying element (D1) connected to the secondary winding to prevent current from being flown through the secondary winding during the forward phase, wherein the output voltage is achieved as the voltage over the first capacitive element. A supplementary circuitry is provided at the secondary side by aid of which the input voltage can be measured on the secondary side, the supplementary circuitry comprising a second capacitive element (CF) and a second rectifying element (D2) connected in series, wherein the supplementary circuitry is connected over the second wiring such that the second rectifying element prevents current from being flown through the supplementary circuitry during the fly-buck phase, wherein the sum of the voltage over the second capacitive element and the output voltage is indicative of the input voltage.
摘要:
A switched mode power supply comprising a switched mode converter and a controller for controlling the switched mode converter, the switched mode converter being provided for converting an input voltage to an output voltage and including, on a primary side, a primary winding and a controllable switch based circuitry connecting the input voltage over the primary winding; and, on a secondary side, a secondary winding coupled to the primary winding and a capacitive element connected over the secondary winding, wherein the output voltage is obtained as the voltage over the capacitive element. The primary winding comprises a first winding portion and at least one further winding portion and the switch based circuitry comprises controllable switches capable of controlling the duty cycle of the switched mode converter and capable of switching between a first operation state wherein the input voltage is connected only over the first winding portion and at least a second operation state wherein the input voltage is connected over the first and the at least one further winding portions, thereby enabling switching between two different transformer ratios. The controller comprises a first control arrangement connected to monitor the output voltage of the switched mode converter and operatively connected to the controllable switches to control the controllable switches to switch to thereby control the duty cycle in response to the monitored output voltage and a reference voltage using PID feedback control. The controller further comprises a second control arrangement connected to monitor the input voltage of the switched mode converter and operatively connected to the controllable switches to control the controllable switches to switch between the first and the at least second operation states in response to the monitored input voltage.
摘要:
A switched mode power supply (400), comprising a transformer (410) having a primary winding (410-1), a transformer core (410-3) configured to store energy transferred thereto from the primary winding (410-1) during operation, and a secondary winding (410-2) having a first terminal (T1) and a second terminal (T2). The switched mode power supply also has a primary side circuit (Q1, Q2, C1) arranged to generate voltage pulses and thereby to drive the primary winding (410-1) of the transformer (410), and a secondary side circuit comprising a rectification circuit connected to the secondary winding (410-2) at the first and second terminals (T1, T2). The rectification circuit is arranged such that during a forward phase of operation of the switched mode power supply, in which the primary winding (410-1) is driven by the primary side circuit to magnetize, and store energy in, the transformer core (410-3), a current induced to flow in the secondary winding (410-2) from the second terminal (T2) to the first terminal (T1) is output by the rectification circuit. The rectification circuit is further arranged such that during a fly-back phase of operation of the switched mode power supply, in which the magnetization of the transformer core (410-3) is reset, a current induced to flow in the secondary winding from the first terminal (T1) to the second terminal (T2) of the secondary winding (410-2) is output by the rectification circuit so that energy stored in the transformer (410) during the forward phase of operation is output by the rectification circuit.
摘要:
A switched mode power supply comprises a switched mode converter (12) and a controller for controlling the switched mode converter, wherein the switched mode converter is provided for converting an input voltage (Vin) to an output voltage (Vout) and includes, on a primary side, a primary winding (X1) and a controllable switch based circuitry (31) connecting the input voltage over the primary winding; and, on a secondary side, a secondary winding (X2) coupled to the primary winding, and a capacitive element (C) connected over the secondary winding, wherein the output voltage is obtained as the voltage over the capacitive element. The primary winding comprises a first winding portion (np1) and at least one further winding portion (np2); and the switch based circuitry comprises controllable switches (Q11, Q41, Q12, Q42, Q21, Q31) capable of switching between a first operation state wherein the input voltage is connected only over the first winding portion and at least a second operation state wherein the input voltage is connected over the first and the at least one further winding portions, thereby enabling switching between two different transformer ratios (n1, n2).