Introduction:
The UC3845 family of control ICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with minimal external parts count. Inter Dalrymple- mentioned circuits include under-voltage lockout feature- ing start-up current less than 1 mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM compare- to which also provides current-limit control, and totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N-Channel MOSFET Transistor, is low in the off-state.
Some Core Parameters:
SPECIAL FEATURES :
● Optimized for off-line and Direct current (DC) to Direct current (DC) converters
● Low start-up current (< 1 ma)
● Automatic feed forward compensa- tion
● Pulse-by-pulse current limiting
● Enhanced load response characteristics
● Under-voltage lockout with hysteresis
● Double pulse suppression
● High current totem pole output
● Internally trimmed bandgap refer-ence
● 500kHz operation
● Low ro error amp
How it Uses in the work:
Internal Block Diagram:
UC3845 Pinout Connections:
Absolute maximum ratings:
● VI Supply Voltage (low impedance source): 30V
● IO Current Output: ± 1A
● EO Output Energy (capacitive load): 5μJ
● Ptot Power Dissipation at Tamb ≤ 50℃ (mini dip, DIP-14): 1W
● Ptot Power Dissipation at Tamb ≤ 25℃ (SO14): 725mW
● Pstg Storage Temperature Range: -65 to 150℃
● TL Lead Temperature (soldering 10s): 300℃
Required
