 2005 Microchip Technology Inc.

DS21927A-page 3

PS2070

factors. The values indicate the maximum battery

voltage.

2.3

Configuration for Lithium Pack

Chemistries

Before attaching the lithium battery pack, please insure

the maximum pack voltage. Attach the battery pack to

the JBat connector by attaching the top of the pack

(positive) to the left most pin (looking into the connec-

tor) and the bottom of the pack (negative) to the right

most pin.

2.4

Configuration for Nickel Pack

Chemistries

Rechargeable nickel based battery packs can be

attached to the PS2070. Before attaching battery cells,

configured for the maximum pack voltage. Attach the

battery pack to the JBat connector by attaching the top

of the pack (positive) to the left most pin (looking into

the connector) and the bottom of the pack (negative) to

the right most pin.

2.5

Configuration for Lead Acid

Chemistries

Lead acid configuration will be updated when firmware

is available.

3.0

FUNCTIONAL DESCRIPTION

3.1

PS2070 Switch Mode Charger

Evaluation

The Switch Mode Charger Evaluation Board includes a

simple buck topology charger using the PS200 IC. The

PS200 monitors the battery to determine its status. The

control is a dual loop design with hardware based

current feedback control and firmware based voltage

feedback control. The hardware is configured as a

constant current loop, controlling the Pulse-Width

Modulator (PWM). The firmware sets the current level by

The firmware also measures the voltage and dynami-

cally adjusts the current to maintain the fully charged

constant voltage value. Please refer to the “PS200 Data

Sheet” for details on configuring the PS200.

Overvoltage

protection

–

the

PS200

provides

overcharge protection. This circuit can be disabled by

leaving all OVP jumper positions open. JP18 should

still be connected.

Jumper Position

1-8

(1 Cell)

2-7

(2 Cells)

3-6

(3 Cells)

4-5

(4 Cells)

5V

X

O

O

O

10V

O

X

O

O

15V

O

O

X

O

16.8V

O

O

O

X

Legend: O = open, X = connect