330

Ω

1 k

Ω

500

Ω

To Current-Sense

Resistor

Shutdown

Shutdown

COMP

0.1

µF

R1

R2

C

TL2843B-Q1

SLVSAE2A

– JULY 2010 – REVISED FEBRUARY 2012

www.ti.com

Shutdown Technique

1 V or pull the COMP terminal below a voltage two diode drops above ground. Either method causes the output

of the PWM comparator to be high (see the Functional Block Diagram). The PWM latch is reset dominant so that

removed. In one example, an externally latched shutdown can be accomplished by adding an SCR that resets by

Figure 5. Shutdown Techniques

A fraction of the oscillator ramp can be summed resistively with the current-sense signal to provide slope

compensation for converters requiring duty cycles over 50% (see Figure 6). Note that capacitor C forms a filter

with R2 to suppress the leading-edge switch spikes.

Figure 6. Slope Compensation

12

Submit Documentation Feedback

Copyright

© 2010–2012, Texas Instruments Incorporated

Product Folder Link(s): TL2843B-Q1