Texas Instruments

The UCC28521 and UCC28528 combination PFC/PWM controllers provide complete control functionality for any off-line power system requiring compliance with the IEC1000-3-2 harmonic reduction requirements. By combining the control and drive signals for the PFC and the PWM stages into a single device, significant performance and cost benefits are gained. Based on the UCC28511, the new devices employ an average current mode control architecture with input voltage feedforward. The major difference of the UCC28521/28 is the trailing-edge / trailing-edge (TEM/TEM) modulation scheme for the PFC/PWM stages. The UCC28528 differs from the UCC28521 as its PWM stage does not turn off with the falling bulk voltage. The UCC28528 PWM was designed for low power auxiliary supplies. These devices offer performance advantages over earlier generation combination controllers. A key PWM feature is programmable maximum duty cycle. For the PFC stage, the devices feature an improved multiplier and the use of a transconductance amplifier for enhanced transient response. The core of the PFC section is in a three-input multiplier that generates the reference signal for the line current. The UCC28521/28 features a highly linearized multiplier circuit capable of producing a low distortion reference for the line current over the full range of line and load conditions. A low-offset, high-bandwidth current error amplifier ensures that the actual inductor current (sensed through a resistor in the return path) follows the multiplier output command signal. The output voltage error is processed through a transconductance voltage amplifier. The transient response of the circuit is enhanced by allowing a much faster charge/discharge of the voltage amplifier output capacitance when the output voltage falls outside a certain regulation window. A number of additional features such as UVLO circuit with selectable hysteresis levels, an accurate reference voltage for the voltage amplifier, zero power detect, OVP/enable, peak current limit, power limiting, high-current output gate driver characterize the PFC section. The PWM section features peak current mode control (with a ramp signal available to add slope compensation), programmable soft-start, accurate maximum duty cycle clamp, peak current limit and high-current output gate driver. The PWM stage is suppressed until the PFC output has reached 90% of its programmed value during startup. During line dropout and turn off, the UCC28521 allows the PWM stage to operate until the PFC output has dropped to 71% of its nominal bulk output value. The UCC28528 on the other hand allows the PWM stage to operate continuously until the bias falls below the UVLO turn-off threhold. Both devices are available in 20-pin DW package. The UCC28521 and UCC28528 combination PFC/PWM controllers provide complete control functionality for any off-line power system requiring compliance with the IEC1000-3-2 harmonic reduction requirements. By combining the control and drive signals for the PFC and the PWM stages into a single device, significant performance and cost benefits are gained. Based on the UCC28511, the new devices employ an average current mode control architecture with input voltage feedforward. The major difference of the UCC28521/28 is the trailing-edge / trailing-edge (TEM/TEM) modulation scheme for the PFC/PWM stages. The UCC28528 differs from the UCC28521 as its PWM stage does not turn off with the falling bulk voltage. The UCC28528 PWM was designed for low power auxiliary supplies. These devices offer performance advantages over earlier generation combination controllers. A key PWM feature is programmable maximum duty cycle. For the PFC stage, the devices feature an improved multiplier and the use of a transconductance amplifier for enhanced transient response. The core of the PFC section is in a three-input multiplier that generates the reference signal for the line current. The UCC28521/28 features a highly linearized multiplier circuit capable of producing a low distortion reference for the line current over the full range of line and load conditions. A low-offset, high-bandwidth current error amplifier ensures that the actual inductor current (sensed through a resistor in the return path) follows the multiplier output command signal. The output voltage error is processed through a transconductance voltage amplifier. The transient response of the circuit is enhanced by allowing a much faster charge/discharge of the voltage amplifier output capacitance when the output voltage falls outside a certain regulation window. A number of additional features such as UVLO circuit with selectable hysteresis levels, an accurate reference voltage for the voltage amplifier, zero power detect, OVP/enable, peak current limit, power limiting, high-current output gate driver characterize the PFC section. The PWM section features peak current mode control (with a ramp signal available to add slope compensation), programmable soft-start, accurate maximum duty cycle clamp, peak current limit and high-current output gate driver. The PWM stage is suppressed until the PFC output has reached 90% of its programmed value during startup. During line dropout and turn off, the UCC28521 allows the PWM stage to operate until the PFC output has dropped to 71% of its nominal bulk output value. The UCC28528 on the other hand allows the PWM stage to operate continuously until the bias falls below the UVLO turn-off threhold. Both devices are available in 20-pin DW package.

The UCC28600-Q1 is a PWM controller with advanced energy features to meet stringent world-wide energy efficiency requirements. UCC28600-Q1 integrates built-in advanced energy saving features with high level protection features to provide cost effective solutions for energy efficient power supplies. UCC28600-Q1 incorporates frequency fold back and green mode operation to reduce the operation frequency at light load and no load operations. UCC28600-Q1 is offered in the 8-pin SOIC (D) package. Operating ambient temperature range is –40°C to 105°C. The Design Calculator, (Texas Instruments Literature number SLVC104), located in the Tools and Software section of the UCC28600-Q1 product folder, provides a user-interactive iterative process for selecting recommended component values for an optimal design. The UCC28600-Q1 is a PWM controller with advanced energy features to meet stringent world-wide energy efficiency requirements. UCC28600-Q1 integrates built-in advanced energy saving features with high level protection features to provide cost effective solutions for energy efficient power supplies. UCC28600-Q1 incorporates frequency fold back and green mode operation to reduce the operation frequency at light load and no load operations. UCC28600-Q1 is offered in the 8-pin SOIC (D) package. Operating ambient temperature range is –40°C to 105°C. The Design Calculator, (Texas Instruments Literature number SLVC104), located in the Tools and Software section of the UCC28600-Q1 product folder, provides a user-interactive iterative process for selecting recommended component values for an optimal design.

The UCC2863x targets high-power, primary-side regulated flyback converters. The ability to operate in both CCM and DCM make the device suitable for applications with a wide power range. The peak power mode allows transient peak power delivery up to 200% of nominal rating, with only a 25% peak current increase, maximizing transformer utilization. The transformer bias winding is used to sense output voltage for regulation, and for low-loss input voltage sensing. Advanced sampling techniques allow CCM operation, and deliver excellent output voltage regulation performance for opto-coupler-less designs at power levels of 100 W and above. A high-voltage current source enables fast and efficient start-up. Advanced light-load modes are deployed to reduce both controller and system power consumption at no load and light load. These modes enable potential system designs to meet 30-mW no-load power for power designs up to 30 W nominal, 60 W peak. The device has been designed for ease-of-use and incorporates many features to enable a wide range of designs. Extensive protection features are included to simplify system design. See the Device Comparison Table for details. The UCC2863x targets high-power, primary-side regulated flyback converters. The ability to operate in both CCM and DCM make the device suitable for applications with a wide power range. The peak power mode allows transient peak power delivery up to 200% of nominal rating, with only a 25% peak current increase, maximizing transformer utilization. The transformer bias winding is used to sense output voltage for regulation, and for low-loss input voltage sensing. Advanced sampling techniques allow CCM operation, and deliver excellent output voltage regulation performance for opto-coupler-less designs at power levels of 100 W and above. A high-voltage current source enables fast and efficient start-up. Advanced light-load modes are deployed to reduce both controller and system power consumption at no load and light load. These modes enable potential system designs to meet 30-mW no-load power for power designs up to 30 W nominal, 60 W peak. The device has been designed for ease-of-use and incorporates many features to enable a wide range of designs. Extensive protection features are included to simplify system design. See the Device Comparison Table for details.

The UCC2863x targets high-power, primary-side regulated flyback converters. The ability to operate in both CCM and DCM make the device suitable for applications with a wide power range. The peak power mode allows transient peak power delivery up to 200% of nominal rating, with only a 25% peak current increase, maximizing transformer utilization. The transformer bias winding is used to sense output voltage for regulation, and for low-loss input voltage sensing. Advanced sampling techniques allow CCM operation, and deliver excellent output voltage regulation performance for opto-coupler-less designs at power levels of 100 W and above. A high-voltage current source enables fast and efficient start-up. Advanced light-load modes are deployed to reduce both controller and system power consumption at no load and light load. These modes enable potential system designs to meet 30-mW no-load power for power designs up to 30 W nominal, 60 W peak. The device has been designed for ease-of-use and incorporates many features to enable a wide range of designs. Extensive protection features are included to simplify system design. See the Device Comparison Table for details. The UCC2863x targets high-power, primary-side regulated flyback converters. The ability to operate in both CCM and DCM make the device suitable for applications with a wide power range. The peak power mode allows transient peak power delivery up to 200% of nominal rating, with only a 25% peak current increase, maximizing transformer utilization. The transformer bias winding is used to sense output voltage for regulation, and for low-loss input voltage sensing. Advanced sampling techniques allow CCM operation, and deliver excellent output voltage regulation performance for opto-coupler-less designs at power levels of 100 W and above. A high-voltage current source enables fast and efficient start-up. Advanced light-load modes are deployed to reduce both controller and system power consumption at no load and light load. These modes enable potential system designs to meet 30-mW no-load power for power designs up to 30 W nominal, 60 W peak. The device has been designed for ease-of-use and incorporates many features to enable a wide range of designs. Extensive protection features are included to simplify system design. See the Device Comparison Table for details.

The UCC2863x targets high-power, primary-side regulated flyback converters. The ability to operate in both CCM and DCM make the device suitable for applications with a wide power range. The peak power mode allows transient peak power delivery up to 200% of nominal rating, with only a 25% peak current increase, maximizing transformer utilization. The transformer bias winding is used to sense output voltage for regulation, and for low-loss input voltage sensing. Advanced sampling techniques allow CCM operation, and deliver excellent output voltage regulation performance for opto-coupler-less designs at power levels of 100 W and above. A high-voltage current source enables fast and efficient start-up. Advanced light-load modes are deployed to reduce both controller and system power consumption at no load and light load. These modes enable potential system designs to meet 30-mW no-load power for power designs up to 30 W nominal, 60 W peak. The device has been designed for ease-of-use and incorporates many features to enable a wide range of designs. Extensive protection features are included to simplify system design. See the Device Comparison Table for details. The UCC2863x targets high-power, primary-side regulated flyback converters. The ability to operate in both CCM and DCM make the device suitable for applications with a wide power range. The peak power mode allows transient peak power delivery up to 200% of nominal rating, with only a 25% peak current increase, maximizing transformer utilization. The transformer bias winding is used to sense output voltage for regulation, and for low-loss input voltage sensing. Advanced sampling techniques allow CCM operation, and deliver excellent output voltage regulation performance for opto-coupler-less designs at power levels of 100 W and above. A high-voltage current source enables fast and efficient start-up. Advanced light-load modes are deployed to reduce both controller and system power consumption at no load and light load. These modes enable potential system designs to meet 30-mW no-load power for power designs up to 30 W nominal, 60 W peak. The device has been designed for ease-of-use and incorporates many features to enable a wide range of designs. Extensive protection features are included to simplify system design. See the Device Comparison Table for details.

The UCC28700-Q1 of flyback power supply controllers provides Constant-Voltage (CV) and Constant-Current (CC) output regulation without the use of an optical coupler. The devices process information from the primary power switch and an auxiliary flyback winding for precise control of output voltage and current. Low start-up current, dynamically controlled operating states and a tailored modulation profile support very low standby power without sacrificing start-up time or output transient response. Control algorithms in the UCC28700-Q1 allows operating efficiencies to meet or exceed applicable standards. The output drive interfaces to a MOSFET power switch. Discontinuous Conduction Mode (DCM) with valley switching reduces switching losses. Modulation of switching frequency and primary current peak amplitude (FM and AM) keeps the conversion efficiency high across the entire load and line ranges. The controllers have a maximum switching frequency of 130 kHz and always maintain control of the peak-primary current in the transformer. Protection features help keep primary and secondary component stresses in check. The UCC28700-Q1 allows the level of cable compensation to be programmed. The UCC28700-Q1 of flyback power supply controllers provides Constant-Voltage (CV) and Constant-Current (CC) output regulation without the use of an optical coupler. The devices process information from the primary power switch and an auxiliary flyback winding for precise control of output voltage and current. Low start-up current, dynamically controlled operating states and a tailored modulation profile support very low standby power without sacrificing start-up time or output transient response. Control algorithms in the UCC28700-Q1 allows operating efficiencies to meet or exceed applicable standards. The output drive interfaces to a MOSFET power switch. Discontinuous Conduction Mode (DCM) with valley switching reduces switching losses. Modulation of switching frequency and primary current peak amplitude (FM and AM) keeps the conversion efficiency high across the entire load and line ranges. The controllers have a maximum switching frequency of 130 kHz and always maintain control of the peak-primary current in the transformer. Protection features help keep primary and secondary component stresses in check. The UCC28700-Q1 allows the level of cable compensation to be programmed.