器件名称: UC1823B
功能描述: High Speed PWM Controller
文件大小: 303.38KB 共15页
简 介:www.ti.com
UC1823A, UC2823A, UC2823B, UC3823A, UC3823B, UC1825A, UC2825A, UC2825B, UC3825A, UC3825B
SLUS334C AUGUST 1995 REVISED AUGUST 2004
HIGHSPEED PWM CONTROLLER
FEATURES D Improved Versions of the UC3823/UC3825 D D D D
PWMs Compatible with Voltage-Mode or Current-Mode Control Methods Practical Operation at Switching Frequencies to 1 MHz 50-ns Propagation Delay to Output High-Current Dual Totem Pole Outputs (2-A Peak) Trimmed Oscillator Discharge Current
DESCRIPTION
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 A, 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.
D D Low 100-A Startup Current D Pulse-by-Pulse Current Limiting Comparator D Latched Overcurrent Comparator With Full
Cycle Restart
BLOCK DIAGRAM
CLK/LEB 4 RT 5 OSC CT 6 RAMP 7 EAOUT 3 NI 2 E/A INV 1 1.25 V
(60%) * R SD PWM LATCH T
13 VC 11 OUTA
14 OUTB 12 P……
