CS5111

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8

Figure 11. Block Diagram of the 1.4 A Current Mode Control Switching Regulator Portion of the

CS5111 in a Boost Configuration

Overvoltage

Bandgap

Reference

64.9 k

Ω

Switcher

Error

Amplifier

ENABLE

Oscillator

COMP

COMP

Logic

Current Sense Amplifier

Base Drive

+

–

+

–

Switcher Shutdown

1.25 V

Multiplexer

GND

1.4 A

SELECT

–

+

Figure 12. Voltage and Current Waveforms

for Boost Topology in CS5111

t

t

t

0

0

0

PROTECTION CIRCUITRY

overvoltage threshold, the drive to the linear and switcher

excessive power dissipation in the linear output transistor

over the output range of 0 V to regulation. Also, the current

function in the switcher output transistor.

If the die temperature is increased above 160

°C, either due

to excessive ambient temperature or excessive power

dissipation, the drive to the linear output transistor is

reduced proportionally with increasing die temperature.

temperature above 160

°C. Since the switcher control

circuitry

is

powered

through

performance, including current limit, will be affected by the