44 results about "CCM mode" patented technology

In a voltage mode buck converter having a pair of switches connected in series by a phase node to be switched by a pair of drive signals generated from a first control signal, a phase resistor is connected between a multifunction pin and the phase node, and a controller generates a second control signal and a third control signal from the second drive signal to sense the voltage on the multifunction pin respectively to generate an over-current signal and a CCM mode switch signal to switch the converter between a CCM mode and a DCM mode.

The invention discloses a totem-pole bridgeless power factor correction circuit which comprises a switching tube series branch and a rectifier diode series branch, and also comprises two series diodes and two parallel diodes, wherein the switching tube series branch is provided with a first switching tube and a second switching tube, the rectifier diode series branch is provided with a first rectifier diode and a second rectifier diode, the two series diodes are respectively serially connected between the first switching tube and a negative busbar and between the second switching tube and a positive busbar, the two parallel diodes are respectively connected in parallel between a common terminal of the first switching tube and the positive busbar and between the common terminal of the second switching tube and the negative busbar, wherein reverse recovery time of the parallel diodes corresponding to the first switching tube is less than that of the first switching tube, and reverse recovery time of the parallel diodes corresponding to the second switching tube is less than that of the second switching tube. Because reverse recovery characteristics of the parallel diodes are better, a reverse recovery current is smaller without damaging the totem-pole bridgeless power factor correction (PFC) circuit working in a CCM (Coincident-Current Memory) mode.

The present invention relates to a switching power supply converter control circuit and a control method thereof. The circuit comprises an output signal sampling and holding module, an error amplifier, a serrated signal generator, a PWM comparator, a demagnetization detection comparator, a timing module, a demagnetization time maintenance iteration module, a positive degree side median current sampling module, a constant current calculation module and a peak value current comparator. Through adoption of the coupling relation of the transformer secondary coil and the auxiliary coil, the output signal sampling and holding module samples the feedback signals showing the voltage of the secondary coil at the transformer demagnetization stage; the sampling signals and the standard voltage are amplified through the error amplifier, the output of the error amplifier and the serrated signals are modulated to generate PWM signals to control the conduction of the power tube; and at the power tube conduction stage, the pressure drop of the positive degree side power sampling resistor is larger than the threshold voltage calculated by a constant current loop, and the power tube is turned off. The switching power supply converter control circuit and the control method thereof allow the switching power supply worked in the CCM mode to realize the constant voltage function in various work modes.

Cryptographic systems and methods that support multiple modes of operation, such as CBC, CTR and/or CCM modes. In one aspect, a method for encrypting data includes reading a plaintext data block from a memory, storing the plaintext data block in an input buffer, encrypting the plaintext data block in the input buffer using a first mode to generate a first ciphertext, storing the first ciphertext in an output buffer, encrypting the plaintext data block in the input buffer using a second mode to generate a second ciphertext. For example, in a CCM mode of operation wherein the first mode is a CTR (counter) mode and the second mode is a CBC (cipher block chaining) mode, the block of plaintext that is initially read from memory and stored in the data input register is applied to both the CTR and CBC modes, thereby reducing a number memory read operations as in conventional CCM modes.

The invention discloses a power factor correction converter with a wide load range. When the converter works in a CCM mode in a full load way, traditional average current control is used as a control strategy; and when the converter works in MCM and DCM modes in a light load way, improved average current control is used as the control strategy. Inductive current sampling correction is increased so that the current obtained by sampling equals to an average value, the feedforward value of duty ratios suitable for CCM and DCM modes undergoes mode discrimination and is then added to a duty ratio calculated by a current loop to obtain a final duty ratio which is used to control a switch tube, and power factor correction is realized. The power factor correction converter with the wide load range overcomes the problems that a traditional PFC converter needs to change a hardware circuit and a control algorithm when working in the light load way, average current control is combined with duty ratio feedwarding to solve the problem that prediction current control is sensitive to circuit parameters, more stable control is easy to realize, and a DCM algorithm based on average current is low in change amount and easy to realize.

The invention discloses a novel three-port Boost integrated converter for a photovoltaic energy storage system. The three-port Boost integrated converter only has one switching transistor. An inductorL1 works in a DCM mode, and an inductor L2 works in a CCM mode. By using a PWM+PFM hybrid modulation strategy and adjusting a duty cycle D and a switching frequency fs, PFM closed-loop control is applied to the photovoltaic array terminal voltage and PWM closed-loop control is applied to the load terminal voltage so as to control the photovoltaic array terminal voltage and the load terminal voltage. Compared with the main circuit of a traditional photovoltaic energy storage system which is formed by a cascaded Boost photovoltaic interface PWM converter and Boost energy storage interface PWM converter, the provided three-port Boost integrated converter removes one switching transistor and its driving module, improve system integration and efficiency, and reduce costs.

The invention discloses a method for generating a root key in a secure trusted execution environment (TEE). The method includes the following steps: S1, calculating the formula Key1=PBKDF2(Password, Salt, it), wherein Password is a password input by a user, Salt is a random number generated internally by the TEE, and it is the number of iterations; S2, calculating a root key UserRootKey=Argon2(Key1, HWUID, Salt, SecretFactor, it, M), wherein M is a memory occupancy value, SecretFactor is a confidentiality factor that is built in a TEE operating system and protected by a confusion technique, and HWUID is a hardware unique identification number; S3, calculating the formula Key3=Argon2(UserRootKey, Salt, it, M); and S4, generating a data encryption key DEK and a random number Nonce in a CCM mode by using a random number generator, and calculating the formula EDEK=AES-CCM(UserRootKey, DEK, Nonce). The scheme of the invention has the beneficial effect that by adding a user PIN as another input factor derived from the root key, the security and reliability of the root key can be enhanced.

The invention relates to a power factor correction circuit for reducing the harmonic distortion of an LED (light-emitting diode) drive circuit, which adopts an average current mode in a CCM (continuous conduction mode). The circuit comprises a multiplier, an operational amplifier and a PFC (power factor correction) comparison amplifier, wherein the circuit adopts a corrected input current (Isense), and a signal obtained after the input current (Isense) is changed with an input voltage is taken as an input end of the multiplier; a current value obtained by virtue of a resistor after a line voltage (IAC) of an alternating voltage of the circuit is rectified is taken as another input end of the multiplier; and an average value (Vrms) end of the input voltage adopts a squarer, and an LED lamp is driven by using a CCM technique.

The invention discloses an improved wide load range boost type power factor correction converter, comprising a main circuit (1) and a control circuit (2). The main circuit (1) comprises an AC source (3), a rectifier bridge circuit (4), a Boost circuit (5), and a load (6). The control circuit (2) comprises a sampling correction module (7), a voltage loop module (8), a current loop module (9), and aPWM module (10). The invention is characterized in that the output of the AC source (3) is connected to the input of the rectifier bridge circuit (4), turning into steamed bread wave, which is used as the input end of the Boost circuit (5); the load (6) is connected to two ends of the output capacitor (Co) of the Boost circuit (5) in parallel; the control circuit parts (7, 8, 9, 10) are control signals in the internal DSP; the output of the sampling correction module (7) and the voltage ring module (8) is used as the input of the current ring module (9), and the output of the current ring module (9) is used as the input of the PWM module (10). The invention is advantageous in that when a converter works in a CCM mode, the correction method brought forward will not affect the duty ratio; as for the PFC converter with wide-load range, the same program is adopted for correction, and the calculation time of the program can be reduced.

The invention discloses a three-port integrated converter for a photovoltaic energy storage system; the converter comprises two switch tubes, three capacitors, three diodes and three inductors, wherein the three capacitors are connected with a storage battery, a photovoltaic module and a load in parallel respectively. The first switch tube, the second switch tube, the first diode, the second diodeand the first inductor form a Buck-BOOST circuit, so that bidirectional flow of energy of the storage battery and the photovoltaic module is realized; and the first switch tube, the third diode and the second inductor form a Boost circuit, so that the energy flow of the photovoltaic assembly to the load is realized. According to the converter, the power switch is integrated through multiplexing of the switch tubes, so that a switch tube and a driving module are reduced, the integration degree of the converter is improved, and the cost is lowered. The invention further discloses a control method of the converter. The first inductor is controlled to work in a CCM mode, and the maximum power point tracking control of the photovoltaic module is realized by adopting a variable duty ratio; andthe second inductor is controlled to work in a DCM mode, and load constant-voltage control is realized by adopting variable-frequency control.

The invention discloses a power factor correction method for LED (light-emitting diode) lighting, which adopts an average current control mode in a CCM (continuous conduction mode). The method comprises the following steps that: after an input alternating voltage is rectified, the rectified voltage is converted into a first current signal (IAC) by a resistor (RAC); the waveform of the first current signal (IAC) is the envelope of the input rectified voltage, the signal and a detection current (ISENSE) of an inductor are superposed, and after the superposed current is corrected, a second current signal (I) is outputted, and the second current signal (I) is used as an input end of an operation module; and an input-end predicted voltage signal (VRMS) obtained by scaling down in equal proportion and filtering an average value of input voltages is taken as an input end of the operation module.

A control method for improving the output accuracy of a switching power supply in accordance with an embodiment of that present invention, precision control module, error calculation module, the PID module and the PWM module constitute the control system, the control system is connected with the controlled switching power supply to form a closed loop, By detecting an output voltage control mode switch, When the output voltage exceeds the upper limit voltage, the circuit enters the DCM mode by mode switching to reduce the input energy so as to stabilize the output voltage in the regulating range. When the output voltage is lower than the lower limit voltage, the circuit enters the CCM mode by mode switching to increase the input energy so as to quickly restore the output voltage to the regulating range. In the normal regulation process, the output voltage is limited between the upper limit voltage and the lower limit voltage, the voltage output ripple is reduced, and the accuracy is improved.

The invention discloses a synchronous rectification control circuit, and the circuit comprises a primary side circuit and an auxiliary side circuit. The primary side circuit comprises a primary side inductor, a primary side switching tube, and a primary side sampling resistor. The auxiliary side circuit comprises an auxiliary side inductor, an auxiliary switching tube, an auxiliary side first sampling resistor, an auxiliary side second sampling resistor, an auxiliary side capacitor, an auxiliary side load resistor, and a synchronous rectification control chip. The circuit detects the voltage Vd of a leakage end, connected with an auxiliary switching tube SR_MOSFET, of the auxiliary side inductor in a mode of cycle-by-cycle analogy, can enable an IC in a DCM/CCM mode to precisely control the time point of discharging finishing, effectively judges the switching-off point, achieves an advanced switching-off function, and solves a difficult problem that the precise switching-off cannot be achieved at the DCM/CCM modes at the same time in the prior art. The circuit can simplify the peripheral application circuits, and reduces application devices.

The invention discloses a CCM-based micro inverter and a control method thereof. The micro inverter employs a universal ARM chip STM32 as a main control chip of a micro inverter control system, by use of AD conversion of the chip, and the inherent functions of a timer, a temperature sensor and an embedded FLASH and the like, the requirements for micro inverter AD conversion, PWM wave duty ratio control, power failure protection and temperature protection are finished, and the system total cost is lowered; the control method enables a micro inverter flyback transformation circuit to work in a CCM, reduces the switch frequency, enables the control of the universal ARM chip STM32 to be realized, reduces switch loss at the same time, reduces requirements for a filter, further decreases the system cost and improves the working efficiency, and the actual measured highest efficiency can reach 94.63%.

The invention discloses a DCM control method of a wind power generation current transformer BOOST circuit. By use of a digital control technology, operation control is carried out in a microprocessor or a digital signal processor chip through software. The invention describes the mechanism of the DCM of a boost chopper boost circuit under the digital control technology, brings forward a realization method of accurately describing digital discretization control under the DCM, and points out a determining method of the DCM and a CCM (continuous conduction mode). Of course, the method provided by the invention is also applied to the CCM. According to a boost control model in the embodiment of the invention, no stable state errors are generated, and reference current can be accurately tracked.

The invention discloses a quadratic Boost converter with low capacitance voltage stress. The quadratic Boost converter comprises a DC voltage source, two inductors, a switching tube, three diodes, twocapacitors and a load. The drain of the switching tube is connected with one end of the second inductor. The anode of the second diode is connected with the cathode of the third diode. The anode of the first capacitor is connected with the cathode of the first diode, the other end of the second inductor and the cathode of the second capacitor. One end of the first inductor is connected with the anode of the first diode and the anode of the third diode. The anode of the second capacitor is connected with the cathode of the second diode and one end of the load. The positive electrode of the DCvoltage source is connected with the other end of the first inductor and the cathode of the first capacitor. The negative electrode of the DC voltage source is connected with the source of the switching tube and the other end of the load. The first inductor and the second inductor operate in the CCM mode. The converter has only one switching tube and has the characteristics of high gain and low capacitance voltage stress so as to be especially suitable for high voltage and high power application occasion.

The invention is applicable to the technical field of electronics, and provides a driving circuit applied to a synchronous rectification tube, a synchronous rectification circuit and a synchronous rectification device. The driving circuit comprises a first voltage generation circuit, an under-voltage comparator circuit, a synchronous rectification tube starting comparator circuit, a synchronous rectification cutoff comparator circuit, a continuous mode working mechanism circuit, a logic circuit and a driving circuit, a corresponding driving control signal is output by detecting a drain voltagesignal and a system voltage signal of the synchronous rectification tube, and the driving of the synchronous rectification tube is achieved. With the driving circuit provided by the scheme, the starting and the cutoff of the synchronous rectification tube can be effectively controlled, a phenomenon that a primary side and a secondary side communicate with each other can be prevented no matter whether the primary side works in a DCM mode, a QR mode or a CCM mode, so that a secondary flywheeling diode can be effectively substituted by the synchronous tube, and the system efficiency is improved.

The invention relates to a control method for PI (power to loop) resonance of a photovoltaic grid-connected inverter based on switching of CCM (continuous current mode) and DCM (discontinuous current mode). When the absolute value of grid-connected voltage Vo outputted by the photovoltaic inverter is higher than or equal to boundary voltage Vbo, the CCM control method is adopted; when the absolute value of the grid-connected voltage Vo outputted by the photovoltaic inverter is lower than the boundary voltage Vbo, the DCM control method is adopted. Under different working modes, the occupation space ratio of an alternating current small signal is adjusted by a PI resonance controller, so as to obtain the total occupation space ratio. According to the total occupation space ratio, the corresponding PWM (pulse width modulation) wave is generated to control the action of a pre-stage MOS (metal oxide semiconductor) tube, so as to enable the photovoltaic inverter to realize grid-connected output. The control method has the advantages that the harmonics of grid-connected current flowing through a zero point can be effectively eliminated, and the grid-connecting efficiency and grid-connecting quality of the inverter are improved.

The invention discloses an automatic dead time optimization system in a CCM of a primary side feedback type flyback power supply. According to the system, a control system composed of a single-outputDAC midpoint sampling module, a digital control module, a current detection module, a dead time calculation module and a PWM driving module, and a controlled synchronous rectification primary side feedback type flyback converter forms a closed loop; through a DAC sampling mechanism, a primary side current is sampled to calculate a secondary side average current; a primary side average current Imid_p and the secondary side average current Is(tmid) in the CMM are obtained; the secondary side current is input to the dead time calculation module to obtain a reasonable dead time td; finally the PWMdriving module is jointly controlled through a primary side feedback loop and the obtained dead time td; and a primary side switch tube driving signal duty and a secondary side rectifier tube drivingsignal duty_SR are generated, so that the dead time between the closing of a secondary side rectifier tube and the opening of a primary side switch tube in the CCM can be reasonably optimized.

The invention discloses a switching control circuit and method, and a switching power supply system. The switching control circuit comprises an on-time control circuit, an off-time control circuit anda logic circuit. The logic circuit is used for generating a switch control signal gate according to the output signal of the on-time control circuit and the off-time control circuit, and outputting the switch control signal gate to the switch to control the on-time control circuit and the off-time control circuit to the switch. The logic circuit can output a switch control signal gate for controlling the switch to be turned on only after the switching off time length reaches a predetermined proportion of the switching off time length of the previous cycle. The switch control circuit and method of the invention, Switching power supply system, can make blanking time no longer fixed, can be in different occasions, or when the system is unstable adaptive switch conduction point time, can control the adjacent switching cycle more stable, effectively avoid switching cycle abrupt change and inductor current in the earlier stage into the CCM mode, to achieve stable control of the output.

The invention provides a novel LED control drive circuit and relates to the technical field of LED drive. The circuit mainly comprises a power supply module, an LED lighting circuit and an LED dimming circuit. The LED dimming circuit comprises an internal reference voltage generation module, a sampling module, a mean value calculation method, a transconductance amplifier, a comparator, a voltage conversion time module, a MOFET tube which controls on and off of the LED lighting circuit, and a MOFET tube drive module. The positive end of the comparator is connected with voltage VP, and the output end is connected with a voltage conversion time module and the MOFET tube drive module. The positive end of the transconductance amplifier is connected with voltage VJ, and the negative end is connected with voltage VA. The voltage conversion time module converts voltage VG into a pulse signal corresponding to pulse width. The MOFET tube drive module converts the pulse signal into a current signal to drive the MOFET tube. The system can enter a CCM mode to reduce the LED output voltage ripple. Both ends of an LED do not need filter capacitors. The service life of an LED lamp is well protected. An external circuit is simplified. The cost is reduced.

The invention provides an LED driving circuit. The LED driving circuit comprises an AC input switch (110), a rectifying filter module (120) of which the input end is connected with the AC input switch (110), a current regulating module (130) for providing constant current to a loaded LED, and a power supply module (140) of which the input end is connected with the rectifying filtering module (120); the output end of the rectifying filter module (120) is connected to the current regulating module (130). The LED driving circuit (100) further comprises a control module (150); the current regulating module (130) is used for sending a sampling signal to the control module (150); the power supply module (140) supplies working voltage to the control module (150). According to the LED driving circuit, the automatic selecting mode is adopted, thus the circuit can work in the BCM mode in case of high input voltage so as to reduce switch consumption, and the circuit automatically enters the CCM mode in case of low input voltage so as to effectively increase the efficiency of working at low voltage, and moreover, the minimum working voltage is reduced; meanwhile, noise can be avoided.