ACT2804
Rev 2, Feb-04-2016
APPLICATIONS INFORMATION
LED1-4 Refreshing Cycle
Every time when VIN is plugged in or a PB is
pushed, LED1, 2, 3, 4 turns on sequentially at 0.5s
interval, like a LED scanning, and then goes into
corresponding mode defined by PT pin.
LED4 LED3 LED2 LED1 VREG
BAT
BATS
BATP
LED1-4 Fault Alarm Signal
ACT2804
At fault conditions, actions are taken. In the
meantime, all the 4 LEDs turn on/off with 0.5s on
and 0.5s off for 10 seconds to send alarm signal
out. The fault conditions include battery OVP, UVP,
OTP.
BATC
PB
CBD
GND
BATN
LEDS4 LEDS3 LEDS2 LEDS1 PT
PCB Board Layout Guidance
RS4 RS3
RS2 RS1
RPT
When laying out the printed circuit board, the
following checklist should be used to ensure proper
operation of the IC.
Figure 5: LED Indication
1. Arrange the power components to reduce the
AC loop area.
In discharge mode, when battery voltage goes
below LED1 threshold, LED1 starts flashing until
Buck (discharge mode) turns off due to either light
load or Buck UVLO. The flash frequencies for all
the LEDs are 0.5Hz with 1s on and 1s off.
2. Place the decoupling ceramic capacitor as
close to BAT pin as possible. Use different
capacitance combination to get better EMI
performance.
In HZ mode, when PB is pressed for 40ms, Buck
turns on. If VBAT<LED1, LED1 starts flashing until
Buck turns off.
3. Place the decoupling ceramic capacitors close
to VIN pin, VOUT pin, and BAT pin.
Conventional indication patterns could behave to
have two application. Setting RPT=4kΩ to have
“Always On”, setting RPT=12kΩ to have “5s
Indication”. The behaviors for both setting are same
in charge mode.
4. Use copper plane for power GND for best heat
dissipation and noise immunity.
5. Use Kevin sense from sense resistors to CSP
and CSN1, CSN2 pins, and the sense resistor
from BATS and BATP pins.
See below table for more information.
6. SW pad is a noisy node switching. It should be
isolated away from the rest of circuit for good
EMI and low noise operation.
INDICATION PATTERN
RPT
#
7. Thermal pad is connected to GND layer through
vias. PGND and AGND should be single-point
connected.
Conventional
Always On In Discharge
1a
4kΩ
Conventional
5s Indication in Discharge
1b
2
12kΩ
24kΩ
40kΩ
56kΩ
8. RC snubber and external Schottky diode across
SW to PGND can be added as needed for
Breathing
5s Indication in Discharge
reducing
SW
spike and
better
EMI
performance.
Bottom Charging
5s Indication in Discharge
3
Circulating
5s Indication in Discharge
4
Below shows 4 LED indication patterns.
Bottom
Charging
Conventional
Circulating
Breathing
<25%
25%ꢀSOC<50%
50%ꢀSOC<75%
75%ꢀSOC<100%
EOC
Flash
Circulating on
Off
Always on
Breathing on/off
Innovative PowerTM
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