UC3825

具有 9.2V/8.4V UVLO 和 85% 占空比、温度范围为 0°C 至 70°C 的增强型 30V、1.5A 双端 PWM 控制器; • Compatible with Voltage or Current Mode Topologies\n• Practical Operation Switching Frequencies to 1MHz\n• 50ns Propagation Delay to Output\n• High Current Dual Totem Pole Outputs (1.5A Peak)\n• Wide Bandwidth Error Amplifier\n• Fully Latched Logic with Double Pulse Suppression\n• Pulse-by-Pulse Current Limiting\n• Soft Start / Max. Duty Cycle Control\n• Under-Voltage Lockout with Hysteresis\n• Low Start Up Current (1.1mA);

The UC1825 family of PWM control ICs is optimized for high frequency switched mode power supply applications. Particular care was given to minimizing propagation delays through the comparators and logic circuitry while maximizing bandwidth and slew rate of the error amplifier. This controller is designed for use in either current-mode or voltage mode systems with the capability for input voltage feed-forward. Protection circuitry includes a current limit comparator with a 1V threshold, a TTL compatible shutdown port, and a soft start pin which will double as a maximum duty cycle clamp. The logic is fully latched to provide jitter free operation and prohibit multiple pulses at an output. An under-voltage lockout section with 800mV of hysteresis assures low start up current. During under-voltage lockout, the outputs are high impedance. These devices feature totem pole outputs designed to source and sink high peak currents from capacitive loads, such as the gate of a power MOSFET. The on state is designed as a high level.

UC3825

High Speed PWM Controller

UC3825

High Speed PWM Controller

UC3825

High Speed PWM Controller

UC3825

High Speed PWM Controller

UC3825

High Speed PWM Controller

UC3825B

具有 16V/10V UVLO 和 50% 占空比、温度范围为 0°C 至 70°C 的 30V、2A 双端 1MHz PWM 控制器; • Improved Versions of the UC3823/UC3825 PWMs\n• Compatible with Voltage-Mode or Current-Mode Control Methods\n• Practical Operation at Switching Frequencies to 1 MHz\n• 50-ns Propagation Delay to Output\n• High-Current Dual Totem Pole Outputs (2-A Peak)\n• Trimmed Oscillator Discharge Current\n• Low 100-µA Startup Current\n• Pulse-by-Pulse Current Limiting Comparator\n• Latched Overcurrent Comparator With Full Cycle Restart;

The UC3823A and UC3823B and the UC3825A and UC3825B family of PWM controllers are improved versions of the standard UC3823 and UC3825 family. Performance enhancements have been made to several of the circuit blocks. Error amplifier gain bandwidth product is 12 MHz, while input offset voltage is 2 mV. Current limit threshold is assured to a tolerance of 5%. Oscillator discharge current is specified at 10 mA for accurate dead time control. Frequency accuracy is improved to 6%. Startup supply current, typically 100 µA, is ideal for off-line applications. The output drivers are redesigned to actively sink current during UVLO at no expense to the startup current specification. In addition each output is capable of 2-A peak currents during transitions.\n\n Functional improvements have also been implemented in this family. The UC3825 shutdown comparator is now a high-speed overcurrent comparator with a threshold of 1.2 V. The overcurrent comparator sets a latch that ensures full discharge of the soft-start capacitor before allowing a restart. While the fault latch is set, the outputs are in the low state. In the event of continuous faults, the soft-start capacitor is fully charged before discharge to insure that the fault frequency does not exceed the designed soft start period. The UC3825 CLOCK pin has become CLK/LEB. This pin combines the functions of clock output and leading edge blanking adjustment and has been buffered for easier interfacing.\n\n The UC3825A and UC3825B have dual alternating outputs and the same pin configuration of the UC3825. The UC3823A and UC3823B outputs operate in phase with duty cycles from zero to less than 100%. The pin configuration of the UC3823A and UC3823B is the same as the UC3823 except pin 11 is now an output pin instead of the reference pin to the current limit comparator. \"A\" version parts have UVLO thresholds identical to the original UC3823 and UC3825. The \"B\" versions have UVLO thresholds of 16 V and 10 V, intended for ease of use in off-line applications.\n\n Consult the application note, The UC3823A,B and UC3825A,B Enhanced Generation of PWM Controllers, (SLUA125) for detailed technical and applications information.

UC3825A

High Speed PWM Controller

UC3825A

High Speed PWM Controller

UC3825A

HIGH-SPEED PWM CONTROLLER