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PT8A2704WE

P1-P3P4-P6P7-P7
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Simple Fast Charger Controller
12-07-0005 PT0199-8 07/05/12
1
PT8A2704/04A
Product Features
Fast charge of nickel cadmium (NiCd) or nickel-
metal hydride (NiMH) batteries
Fast-charge termination by negative delta voltage,
maximum voltage, maximum temperature, and 90
minutes charging time
Support 1 to 8 cells fast charging
10% (PT8A2704) or 4% (PT8A2704A) of constant
charging current for trickle charging
On-chip 2.0V regulator
On chip precise ADC
Internal RC oscillator with external R&C
components
Low cost 8-pin DIP/SOIC package
Applications
Rechargeable shavers and hair cutters
Rechargeable RC cars
Rechargeable power tools
Product Description
The PT8A2704/04A Fast-Charger IC is low-cost CMOS
battery-charge controller providing reliable charge
termination for both NiCd and NiMH battery
applications, such as Power tool and Consumer
electronics. A current-limited or constant–current supply
allows the PT8A2704/04A to be a cost-effective charger
with only a few external components. The
PT8A2704/04A has programmable charging time and
programmable trickle charging rate control by options in
a single IC for charging NiCd or NiMH battery cells.
For safety, fast or trickle charging is inhibited if the
battery temperature is over a safety threshold. Fast
charge is terminated by any of the following:
- Negative delta voltage/zero delta voltage
- Maximum voltage
- Maximum temperature
- Maximum time
Pin Assignment and Pin Description
PT8A2704/04A
DIP-8 or SOIC-8
Package (Top View)
Pin Description
Pin
No.
Pin
Name
I/O
Description
1
GND
-
Power ground
2
VB
I
Battery voltage input (1.6V – 1.8V)
3
VT
I
NTC voltage input(1.6V – 1.8V)
4
OSC
I
RC oscillator input, external resistor
pull-up and capacitor pull-down
5
CORD
I
Cord detection input
6
VCC
-
Positive power supply voltage
7
CHARGE
O
Charging control enable
8
VEE
O
2.0v regulated voltage
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12-07-0005 PT0199-8 07/05/12
2
PT8A2704/04A
Simple Fast Charger Controller
Block Diagram
Functional Description
Voltage Regulator (2.0V Regulator): Build-in voltage regulator used to power supply RC oscillator, precise ADC.
Oscillator: Internal RC oscillator to generate a 64 kHz clock for internal system.
POR (Power-on Reset): Power on reset to reset all internal logic while power on.
Charging Control: Charging control enables output CHARGE pin which can be used to show charging status. It is logic high
during constant current charging and 12.5Hz with 10% (for PT8A2704) or 4% (for PT8A2704A) duty cycle during trickle current
charging
AC Cord Control: CORD input is external cord detection pin (digital level), active high.
Precision ADC:
VB measures the battery voltage. VB is a divide voltage from the battery voltage. When VB exceeds the maximum voltage
(0.9VEE), fast charging will be terminated. Moreover, VB detects the negative delta voltage during fast charging. It is suggested
to set the termination voltage of VB within the input range of the ADC which is 0.8VEE to 0.9VEE.
VT measures the temperature of the battery with an external NTC (refer to How to determine RX1 on page5). Maximum
temperature termination occurs when the VT exceeds a temperature cut-off threshold voltage (eg. 50˚C
which equivalent to
0.887VEE). Constant current or trickle charging will stop completely when the temperature exceeds another threshold voltage (eg.
55˚C
which equivalent to 0.897VEE).
Charging Cycle Phases
Fast charge is started when the CORD is high. If the battery voltage is over the limit or temperature exceeds 50˚C, pulse-trickle
charge begins and the device charges the battery with trickle charge till the CORD is low (see above Figure).
Fast charge will be termination by one or more of the four possible termination conditions:
negative delta voltage/delta voltage
maximum voltage
maximum temperature
maximum time
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12-07-0005 PT0199-8 07/05/12
3
PT8A2704/04A
Simple Fast Charger Controller
Maximum Ratings
Storage Temperature…………………………………………... -25
o
C to +85
o
C
Supply Voltage to Ground Potential (V
CC
)…………. ……………...…-0.5V to 6V
DC Input Voltage…………………… ……………..……… -0.5V to V
CC
+0.5V
DC Output Current……………………………………………....20mA
Power Dissipation…………………………………………...…500mW
Recommended Operation Condition
Parameters
Description
Min.
Type.
Max.
Unit
V
CC
Operating Voltage
2.2
2.4
5.5
V
ADC V
IN
Input voltage range (VT, VB)
0.8
-
0.9
VEE
Fosc
Frequency of oscillator (C=390pF, R=47kΩohm)
54.4
64
73.6
kHz
T
A
Operation Temperature
0
25
70
˚C
DC Electrical Characteristics
(T
A
= 0~70°C, V
CC
= 2.4V unless otherwise claims)
Symbol
Description
Test Conditions
Min.
Typ.
Max.
Unit
I
IL
, I
IH
Input Low/HIGH leakage current for
CORD pin
V
CC
=2.4V,V
IL
=0.2V, V
IH
=2.2V
-1
-
1
μA
I
OH
Output HIGH current
CHARGE pin, V
OH
=2.2V
-3
-
-
mA
I
OL
Output LOW current
CHARGE pin, V
OL
=0.2V
3
-
1
VEE
Regulator output voltage
No load
1.9
2.0
2.1
V
V
O
Line Regulation of regulator
2.2VV
CC
3.0V, No load
-
-
50
mV
V
LDR
Load regulation
0mA I
L
3mA
-
-
50
mV
VBmax
Maximum battery voltage to stop fast-
charge
-
-
0.9
-
VEE
VTmax
Maximum VT voltage for battery
temperature detection to stop fast-
charge
-
-
0.897
-
VEE
Rslt
Average A/D resolution of ADC
No load
6.00
6.25
6.50
mV
DNL
ADC Differential nonlinearity
No load
-
1
-
LSB
INL
ADC Integral nonlinearity
No load
-
1
-
LSB
I
CC
Supply Current
R=47kΩ, C=390pF, no load
-
-
380
μA
AC Electrical Characteristics
(T
A
= 0~70°C, V
CC
= 2.2V~3.0V)
Symbol
Description
Test Conditions
Min.
Typ.
Max.
Unit
F
OSC
Oscillator Frequency
C=390pF, R=47kΩ
54.4
64
73.6
kHz
T
FC
Maximum fast-charge time
OSC=64kHz
-
90
-
Minutes
DC
Duty-cycle of charge pin output in
trickle charge mode
PT8A2704
7
10
13
%
PT8A2704A
3
4
5
%
Note:
Stresses greater than those listed under MAXIMUM
RATINGS may cause permanent damage to the
device. This is a stress rating only and functional
operation of the device at these or any other condi-
tions above those indicated in the operational sec-
tions of this specification is not implied. Exposure
to absolute maximum rating conditions for extended
periods may affect reliability.
P1-P3P4-P6P7-P7

PT8A2704WE

Mfr. #:
Buy PT8A2704WE
Manufacturer:
Diodes Incorporated
Description:
Battery Management FastChargeController NiCd andNiMH Battery
Lifecycle:
New from this manufacturer.
Delivery:
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