Uc3845 by the additionof an internal toggle flip flop. Data sheet order now. 11 8 3 feature description. Diagram of the uc3842 pwm ic tester 1 1 x 12v 0 12v linear transformer 2 1 x 8 pins ic socket 3 1 x 390 ohm watt resistor 4 1 x 4 7 k ohm potentiometer pot 5 2 x 1n4007 diode 6 1 x 47 microfarad 63 volt capacitor 7 1 x power switch 8 1 x 3 pin plug 9 1 x 3 feet power cable 10 1x led 11 2 x grommets optional 12. The ucx845b is tailored for lower voltage. Thresholds for the uc3843 and uc3845 are 8 5 v. These devices are available in an 8 pin dual in line and surface mount soic 8 plastic package as well as the 14 pin plastic surface mount soic 14. 12 7 9 5 7 4 3 2 1 1 5 3 7 11 8 14 6 10 5 8 gnd comp current sense current sense comparator pwm latch internal bias 5v ref 34v uvlo 16v osc error amp 2r r 1v 2 5v 5 0v 50ma output 6v vref vcc vfb s r rt ct s r. Philips semiconductors linear products product specification current mode pwm controller uc3842. The uc3842 and uc3843 can operate.
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Diagram for easy fixing. Parameters topology boost buck buck boost flyback forward control method peak current mode vcc min v 8 4 vcc max v 28 duty cycle max 50 uvlo thresholds on off v 8 4 7 6 frequency max khz 500 operating temperature range c 0 to 70 gate drive typ a 1 features adjustable switching frequency current limiting dead. The soic 14 package has separate power and ground pins for the totem pole output stage. Which blanks the output off every other clock cycle. Uc3845 by the additionof an internal toggle flip flop. Uc3844 uc3845 0 c to 70 c 6 pin configuration and functions d jg and p packages 8 pin soic cdip and pdip top view d and w packages 14 pin soic and cfp top view fk package 20 pin lccc top view.
Html pages 1. Philips semiconductors linear products product specification current mode pwm controller uc3842. A range of the. Should be connected close to pin 5 in a single point ground. Duty cycle d max uc3842 uc3843 95 97 100 d max uc3844 uc3845 47 48 50 min. Block diagram toggle flip flop used only in uc3844b and uc3845b uvlo s r 5v ref 34v internal bias vref good logic 2 50v t s r osc r1v current sense comparator 2r pwm latch 7 5 4 2 1 3 8 6 error amp. Parameter symbol conditions min. To duty cycles approaching 100. Uc3845 by the additionof an internal toggle flip flop. Thresholds for the uc3843 and uc3845 are 8 5 v.
12 8 4 device functional modes. The ucx845b is tailored for lower voltage. These devices are available in an 8 pin dual in line and surface mount soic 8 plastic package as well as the 14 pin plastic surface mount soic 14. Here are the part lists of this project. A range of the. Duty cycle d min 0 total standby current start up current ist. Uc3844 uc3845 0 c to 70 c 6 pin configuration and functions d jg and p packages 8 pin soic cdip and pdip top view d and w packages 14 pin soic and cfp top view fk package 20 pin lccc top view. Currentmode pwm controller uc3845 datasheet uc3845 circuit uc3845 data sheet. 12 7 9 5 7 4 3 2 1 1 5 3 7 11 8 14 6 10 5 8 gnd comp current sense current sense comparator pwm latch internal bias 5v ref 34v uvlo 16v osc error amp 2r r 1v 2 5v 5 0v 50ma output 6v vref vcc vfb s r rt ct s r. Duty cycle d max uc3842 uc3843 95 97 100 d max uc3844 uc3845 47 48 50 min.
The transistor and 5kω potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3. 20 9 application and implementation. Parameter symbol conditions min. 12 8 4 device functional modes. Parameters topology boost buck buck boost flyback forward control method peak current mode vcc min v 8 4 vcc max v 28 duty cycle max 50 uvlo thresholds on off v 8 4 7 6 frequency max khz 500 operating temperature range c 0 to 70 gate drive typ a 1 features adjustable switching frequency current limiting dead. Uc3845 by the additionof an internal toggle flip flop. Zero to 50 is obtained by the uc3844 and. 11 8 3 feature description. They are specifically designed for off line and dc to dc converter applications offering the designer a cost effective solution with minimal external components. To duty cycles approaching 100.
Which blanks the output off every other clock cycle. Uc3845 by the additionof an internal toggle flip flop. Duty cycle d min 0 total standby current start up current ist. Stmicroelectronics alldatasheet datasheet datasheet search site for electronic. Should be connected close to pin 5 in a single point ground. Uc3844 uc3845 uc2844 uc2845 high performance current mode controllers the uc3844 uc3845 series are high performance fixed frequency current mode controllers. The ucx844b has uvlo thresholds of 16v on and 10v off ideally suited for off line converters. Data sheet order now. Html pages 1. Thresholds for the uc3843 and uc3845 are 8 5 v.
12 8 4 device functional modes. Here are the part lists of this project. These devices are available in an 8 pin dual in line and surface mount soic 8 plastic package as well as the 14 pin plastic surface mount soic 14. Uc3844 uc3845 uc2844 uc2845 high performance current mode controllers the uc3844 uc3845 series are high performance fixed frequency current mode controllers. Duty cycle d max uc3842 uc3843 95 97 100 d max uc3844 uc3845 47 48 50 min. Ioutput q g f sw fosc 1 72 r rt c ct 4. To duty cycles approaching 100. The ucx845b is tailored for lower voltage. Vi ground rt ct vfb comp current sense vref 5v 50ma output d95in331 minidip so8 uc3842b 1 15 all voltages are with respect to pin 5 all currents are positive into the specified terminal. 8 2 functional block diagrams.
