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PL384XBP8 Datasheet(PDF) 1 Page - Cystech Electonics Corp. |
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PL384XBP8 Datasheet(HTML) 1 Page - Cystech Electonics Corp. |
1 / 15 page ![]() CYStech Electronics Corp. Spec. No. : C510P8 Issued Date : 2003.04.24 Revised Date : Page No. : 1/15 PL384XBP8 CYStek Product Specification High Performance Current Mode PWM Controllers PL384XBP8 Description The PL384XBP8 family of control ICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include a trimmed oscillator for precise duty cycle control, under voltage lockout featuring start-up current less than 0.5mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N-channel MOSFETs, is low in the off-state. Differences between members of this family are the under-voltage lockout thresholds and maximum duty cycle ranges. The PL3842B and PL3844B have UVLO thresholds of 16V (on) and 10V (off), ideally suited off-line applications. The corresponding thresholds for the PL3843B and PL3845B are 8.5V and 7.9V. The PL3842B and PL3843B can operate to duty cycles approaching 100%. A range of the zero to <50% is obtained by the PL3844B and PL3845B by the addition of an internal toggle flip flop which blanks the output off every other clock cycle. Features • Trimmed oscillator for precise frequency control • Oscillator frequency guaranteed at 250 kHz • Current mode operation to 500kHz • Automatic feed forward compensation • Latching PWM for cycle-by-cycle current limiting • Internally trimmed reference with undervoltage lockout • High current totem pole output • Undervoltage lockout with hysteresis • Low start-up and operating current Block Diagram( toggle flip flop used only in PL3844B and PL3845B) S/R 5V REF 2.50V VREF GOOD LOGIC INTERNAL BIAS OSC ERROR AMP. 2R R 1V R S T CURRENT SENSE COMPARATOR PWM LATCH VREF 5V50mA OUTPUT 8 6 VI GROUND RT/CT VFB COMP CURRENT SENSE 7 5 34V UVLO 4 2 1 3 PL3842B |