TEA1104/N1 Ver la hoja de datos (PDF) - Philips Electronics

Número de pieza

componentes Descripción

Fabricante

TEA1104/N1

Cost effective battery monitor and fast charge IC for NiCd and NiMH chargers

Philips Electronics 

Philips Semiconductors

Cost effective battery monitor and fast

charge IC for NiCd and NiMH chargers

Objective specification

TEA1104; TEA1104T

PINNING

SYMBOL

GND

NTC

VS

Vbat

Rref

VP

OSC

LED

PIN

DESCRIPTION

1 ground

2 negative temperature coefficient

resistor input

3 stabilized supply voltage

4 battery voltage sensing

5 reference resistor

6 positive supply voltage

7 oscillator input

8 LED output

handbook, halfpage

GND 1

8 LED

NTC 2

Vs 3

Vbat 4

TEA1104

7 OSC

6 VP

5 Rref

MGE353

Fig.2 Pin configuration.

INTRODUCTION

The operation of the TEA1104; TEA1104T is explained

with the aid of the application diagram illustrated in Fig.7.

An application note (AN95085) is available describing the

versatility of the TEA1104; TEA1104T.

An external power current source charges the batteries via

an electronic switch which is controlled by the TEA1104.

The TEA1104 monitors the battery voltage. Fully charged

batteries are detected when the battery voltage peaks. In

fact, a voltage drop of 0.25% with respect to the top value

is detected. Fast charging is initiated at ‘power on’ or at

‘replaced batteries’. The switch is continuously on,

providing that all protection levels are met. At battery full

detection, the charge current is duty cycled to reduce the

average charge current to a lower level, keeping the

batteries fully charged but at he same time assuring long

battery life. In Fig.3 the battery voltage during fast charge

is plotted.

FUNCTIONAL DESCRIPTION

A block diagram of the TEA1104; TEA1104T is illustrated

in Fig.1

Mode latch

The Mode latch determines if the system is in the fast or in

the slow charge mode.

• Fast charge is active at:

– power switch-on and battery connected

– temperature between minimum and maximum value

– battery insert

• Trickle charge is active if:

– battery full is detected

– maximum time is exceeded

– maximum cut-off temperature is exceeded after the

initial phase.

Supply block

For correct start-up, the IC supply current is limited to

35 µA (typ.) until the start-up voltage of 6.4 V is reached

(standby mode). Thereafter, the operating supply voltage

VP has to be within the window of 5.45 to 11.5 V, meaning

that there is no need for an external voltage regulator to

supply the IC.

The supply block delivers the following outputs:

• With the help of an external resistor (pin Rref), a

reference current is obtained which defines the

accuracy of all IC timing characteristics

• Externally available 4.25 V stabilized voltage source

(Vsource). This source is used internally to supply a large

part of the circuit and can be used to set the NTC biasing

and to supply other external circuitry with a maximum

current of 1 mA. Protection information is provided via

VS, to design a dual LED indicator

• Power-on reset pulse resets all digital circuitry after a

start or restart, due to an interrupted VS.

1996 Feb 26

4

Share Link: