Texas Instruments TPS65820 Evaluation Module TPS65820EVM TPS65820EVM データシート
製品コード
TPS65820EVM
POWER PATH MANAGEMENT FUNCTION
Detecting the System Status
POWER PATH
CONTROL LOGIC
AC DETECTED
USB DETECTED
USB OVP
AC OVP
OUT SHORTED
BAT
SHORTED
OUT LOWER
THAN BAT
V
BATSH
AC
USB
OUT
BAT
V
OVP
V
OVP
BAT
V
OUTSH
BAT
OUT
BAT
NO BATT
SHORT
DPPM
1 V
SLVS663B – MAY 2006 – REVISED APRIL 2008
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The TPS65820 regulates the voltage at the OUT pin to 4.6 V, when one of the external supplies connected to
pins AC or USB is powering the OUT pin. The selected input (AC or USB pin) current is limited to a value defined
by I
pins AC or USB is powering the OUT pin. The selected input (AC or USB pin) current is limited to a value defined
by I
2
C register settings. The input current limit function assures compatibility with USB standard requirements,
and also implements a protection function by limiting the maximum current supplied by an external AC_DC
adapter or USB port power terminal.
adapter or USB port power terminal.
The AC power MOSFET and USB power MOSFET operating modes are set by integrated control loops. Each of
the power MOSFETs is controlled by two loops: one system voltage regulation loop and one input current limiting
loop. The integrated loops modulate the AC or USB power MOSFETs drain to source resistance to regulate
either the OUT pin voltage or to limit the input current. If no input power is present (AC and USB input power not
detected) the AC and USB power MOSFETs are turned OFF, and the battery MOSFET is turned ON, connecting
the BAT pin to the OUT pin.
the power MOSFETs is controlled by two loops: one system voltage regulation loop and one input current limiting
loop. The integrated loops modulate the AC or USB power MOSFETs drain to source resistance to regulate
either the OUT pin voltage or to limit the input current. If no input power is present (AC and USB input power not
detected) the AC and USB power MOSFETs are turned OFF, and the battery MOSFET is turned ON, connecting
the BAT pin to the OUT pin.
The battery switch is turned ON when the AC or USB input power is detected and the charger function is
enabled, charging the battery pack. During charge the battery MOSFET switch operation mode is defined by the
charger control loops. The battery MOSFET switch drain-to-source resistance is modulated by the charge current
loop and charge voltage loop in order to implement the battery charging algorithm. In addition ot that multiple
safety functions are activated (thermal shutdown, safety timers, short-circuit recovery), and additional functions
(thermal loop and DPPM loop) optimize the charging process.
enabled, charging the battery pack. During charge the battery MOSFET switch operation mode is defined by the
charger control loops. The battery MOSFET switch drain-to-source resistance is modulated by the charge current
loop and charge voltage loop in order to implement the battery charging algorithm. In addition ot that multiple
safety functions are activated (thermal shutdown, safety timers, short-circuit recovery), and additional functions
(thermal loop and DPPM loop) optimize the charging process.
The power path and charge management block operate independently of the other TPS65820 circuits. Internal
circuits check battery parameters (pack temperature, battery voltage, charge current) and system parameters
(AC and USB voltage, battery voltage detection), setting the power path MOSFETs operating modes
automatically. The TPS65820 has integrated comparators that monitor the battery voltage, AC pin voltage, USB
pin voltage and the OUT pin voltage. The data generated by those comparators is used by the power path
control logic to define which of the integrated power path switches is active. A simplified block diagram for the
system status detection is shown below.
circuits check battery parameters (pack temperature, battery voltage, charge current) and system parameters
(AC and USB voltage, battery voltage detection), setting the power path MOSFETs operating modes
automatically. The TPS65820 has integrated comparators that monitor the battery voltage, AC pin voltage, USB
pin voltage and the OUT pin voltage. The data generated by those comparators is used by the power path
control logic to define which of the integrated power path switches is active. A simplified block diagram for the
system status detection is shown below.
Figure 32. TPS65820 Systems Status Detection, Charger and Power Path Section
44
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