MAX8614BETD(2006) View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAX8614BETD
(Rev.:2006)

Dual-Output (+ and -) DC-DC Converters for CCD

Maxim Integrated 

Dual-Output (+ and -) DC-DC

Converters for CCD

Functional Diagram

ONBST

ONINV

FLT

SEQ

AVCC

BIAS

AND

CONTROL

BLOCK

ERROR

AMPLIFIER PWM

COMPARATOR

MAX8614A

MAX8614B

VCC

INVERTER

CONTROL

LOGIC

LXN

INVERTER

CURRENT SENSE

FBN

1.01V

REFERENCE

1.25V

REF

SOFT-START

1MHz

OSCILLATOR

ERROR

AMPLIFIER PWM

COMPARATOR

STEP-UP

CONTROL

LOGIC

STEP-UP

CURRENT SENSE

PVP

LXP

PGND

FBP

GND

Detailed Description

The MAX8614A/MAX8614B generate both a positive and

negative output voltage by combining a step-up and an

inverting DC-DC converter on one IC. Both the step-up

converter and the inverter share a common clock. Each

output is independently regulated.

Each output is separately controlled by a pulse-width-

modulated (PWM) current-mode regulator. This allows

the converters to operate at a fixed frequency (1MHz)

for use in noise-sensitive applications. The 1MHz

switching rate allows for small external components.

Both converters are internally compensated and are

optimized for fast transient response (see the Load-

Transient Response/Voltage Positioning section).

Step-Up Converter

The step-up converter generates a positive output volt-

age up to 24V. An internal power switch, internal True-

Shutdown load switch (PVP), and external catch diode

allow conversion efficiencies as high as 90%. The inter-

nal load switch disconnects the battery from the load

by opening the battery connection to the inductor, pro-

viding True Shutdown. The internal load switch stays on

at all times during normal operation. The load switch is

used in the control scheme for the converter and can-

not be bypassed.

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