LTC7820

1

7820fc

For more information www.linear.com/LTC7820

TYPICAL APPLICATION

FEATURES

DESCRIPTION

Fixed Ratio High Power

Inductorless (Charge Pump)

DC/DC Controller

The LTC®7820 is a fixed ratio high voltage high power

switched capacitor/charge pump controller. The device

includes four N-channel MOSFET gate drivers to drive

external power MOSFETs in voltage divider, doubler or

inverter configurations. The device achieves a 2:1 step-

down ratio from an input voltage as high as 72V, a 1:2

step-up ratio from an input voltage as high as 36V, or a

1:1 inverting ratio from an input voltage up to 36V. Each

power MOSFET is switched with 50% duty cycle at a

constant pre-programmed switching frequency. System

efficiency can be optimized to over 99%. The LTC7820

provides a small and cost effective solution for high

power, non-isolated intermediate bus applications with

fault protection.

The LTC7820 switching frequency can be linearly

programmedfrom100kHzto1MHz.Thedeviceisavailable

in a thermally enhanced 28-lead QFN package with some

no-connect pins for high voltage compatible pin spacing.

Efficiency and Power Loss

vs Load Current

APPLICATIONS

n

Low Profile, High Power Density, Capable of 500W+

n

Soft Switching: 99% Peak Efficiency and Low EMI

n

n

n

n

Soft Startup into Steady State Operation

n

n

Input Current Sensing and Overcurrent Protection

n

Wide Operating Frequency Range: 100kHz to 1MHz

n

Output Short-Circuit/OV/UV Protections with

Programmable Timer and Retry

n

Thermally Enhanced 28-Pin 4mm × 5mm QFN Package

n

Bus Converters

n

High Power Distributed Power Systems

n

Communications Systems

n

Industrial Applications

All registered trademarks and trademarks are the property of their respective owners. Protected

by U.S. patents, including 9484799.

Very High Efficiency 5A Voltage Divider

0.1µF

10k

10k

10k

40k

4.7µF

10

10µF

7820 TA01a

1µF

1µF

0.1µF

0.1µF

0.1µF

10

100

0.1µF

12V

10µF

×6

10k

UV

HYS_PRGM

PGOOD

FREQ

FAULT

GND

G3

G4

TIMER

G2

LTC7820

BOOST3

SW3

BOOST2

BOOST1

SW1

G1

RUN

48V/24V

24V/12V

5A*

* LOAD CURRENT APPLIED

AFTER STARTUP

0.005

EFFICIENCY

POWER LOSS

LOAD CURRENT (A)

0

1

2

3

4

5

95

96

97

98

99

100

0

0.4

0.8

1.2

1.6

2.0

7820 TA01b