MAX713CPE 데이터 시트보기 (PDF) - Maxim Integrated

부품명

상세내역

제조사

MAX713CPE

NiCd/NiMH Battery Fast-Charge Controllers

Maxim Integrated 

NiCd/NiMH Battery

Fast-Charge Controllers

Detailed Description

The MAX712/MAX713 fast charge NiMH or NiCd batter-

ies by forcing a constant current into the battery. The

MAX712/MAX713 are always in one of two states: fast

charge or trickle charge. During fast charge, the

current level is high; once full charge is detected, the

current reduces to trickle charge. The device monitors

three variables to determine when the battery reaches

full charge: voltage slope, battery temperature, and

charge time.

1.5

1.4

VOLTAGE

1.3

TEMPERATURE

0.4

0

A

mA

μA

12

3

1. NO POWER TO CHARGER

TIME

2. CELL VOLTAGE LESS THAN 0.4V

3. FAST CHARGE

4. TRICKLE CHARGE

5. CHARGER POWER REMOVED

45

Figure 2. Typical Charging Using Voltage Slope

Figure 1 shows the block diagram for the MAX712/

MAX713. The timer, voltage-slope detection, and temper-

ature comparators are used to determine full charge

state. The voltage and current regulator controls output

voltage and current, and senses battery presence.

Figure 2 shows a typical charging scenario with batteries

already inserted before power is applied. At time 1, the

MAX712/MAX713 draw negligible power from the bat-

tery. When power is

power-on reset circuit

applied

(see the

PtOo WDECR-_INON(t-_imREeSE2T),

the

sig-

nal in Figure

charge. Once

P1)OWhoEldRs-_OthNe-_RMEASXE7T1g2o/eMsAhXig7h1,3thine

trickle

device

enters the fast-charge state (time 3) as long as the cell

voltage is above the undervoltage lockout (UVLO) volt-

age (0.4V per cell). Fast charging cannot start until (bat-

tery voltage)/(number of cells) exceeds 0.4V.

When the cell voltage slope becomes negative, fast

charge is terminated and the MAX712/MAX713 revert

to trickle-charge state (time 4). When power is removed

(time 5), the device draws negligible current from the

battery.

Figure 3 shows a typical charging event using tempera-

ture full-charge detection. In the case shown, the bat-

tery pack is too cold for fast charging (for instance,

brought in from a cold outside environment). During

time 2, the MAX712/MAX713 remain in trickle-charge

state. Once a safe temperature is reached (time 3), fast

charge starts. When the battery temperature exceeds

the limit set by THI, the MAX712/MAX713 revert to trick-

le charge (time 4).

THI

TLO

A

mA

μA

12

3

4

1. NO POWER TO CHARGER

TIME

2. CELL TEMPERATURE TOO LOW

3. FAST CHARGE

4. TRICKLE CHARGE

Figure 3. Typical Charging Using Temperature

VREF = VLIMIT

1.5

1.4

1.3

A

mA

μA

1

1. BATTERY NOT INSERTED

2. FAST CHARGE

3. TRICKLE CHARGE

4. BATTERY REMOVED

2

TIME

34

Figure 4. Typical Charging with Battery Insertion

8 _______________________________________________________________________________________

Share Link: