2-445

Application Information

Theory of Operation

The HIP6200 is used in conjunction with a switching DC-DC

converter to provide a regulated DC voltage. The output

voltage of a DC-DC converter changes instantly with sudden

load changes characteristic of today’s microprocessors. This

change occurs because the bulk capacitors are imperfect;

they have parasitic resistances (ESR) and inductances (ESL)

which translate into voltage drops as the load is initially

supplied by the bulk capacitance. Also, due to its output

inductor, the DC-DC converter takes about 10-20

µs (typical)

before it provides the load current required by the CPU. The

HIP6200 contains two high-speed linear regulators which are

inactive except during the converter response time after high

di/dt load transients. When active, the linear regulators

maintain a small difference between the desired and actual

output voltage.

The Typical Application Diagrams below illustrate how the

DeCAPitator functions. The left side shows a common DC-

DC converter response to a fast ‘low-to-high’ load transient.

The right side shows a similar response with a HIP6200

circuit employed. The HIP6200 allows the use of fewer bulk

capacitors to handle the regulation requirements of the high

edge-rate load transients. The response time of the

HIP6200’s linear regulators (100ns typical) are fast enough

to help with the leading edge spike. Output voltage

deviations during the converter response time are reduced

with the HIP6200 since it helps supply the load while the

inductor current slews.

Typical Application Diagrams

FIGURE 1. PORTABLE CPU WITHOUT HIP6200, HIP6201

FIGURE 2. PORTABLE CPU WITH HIP6200, HIP6201

CPU

LOAD

PWM

CONTROLLER

BATTERY

POWER

CONVERTER

+5V

CPU

LOAD

CAP

OUT

GND

EN

SNS

PGND

4

8

5

3

2

6

7

1

HIP6201

BATTERY

POWER

PWM

CONTROLLER

HIP6200, HIP6201