Texas Instruments bq24650, User Manual, Page: 3 / 19

OUT
R13
V = 2.1 V 1 +
R15
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÷
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MPPSET
R17
V = 1.2 V 1 +
R19
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Introduction
1.4 Control and Key Parameters Settings
Table 2. Control and Key Parameters Settings
Jack Description Factory Setting
JP1 Select external TS input or internal valid TS setting Jumper ON 1-2 (external TS)
1-2 : External TS input
2-3 : Internal valid TS setting
JP2 The pullup power source supplies the LEDs when JP2 ON. LED has no Jumper ON (LED power available)
power source when JP2 is OFF.
JP3 TERM_EN setting Jumper ON 2-3 (enable termination)
2-3 : Connect TERM_EN to VREF to enable termination
1-2 : Connect TERM_EN to GND to disable termination
JP4 Charger enable/disable setting. MPPSET is pulled to GND and the charger Jumper OFF (disable charger)
is disabled when JP4 OFF; charger is enabled when JP4 is ON.
1.5 Recommended Operating Conditions
Table 3. Recommended Operating Conditions
Symbol Description Min Typ Max Unit Notes
Supply voltage, V
IN
Input voltage 5 20 28 V
Battery voltage, V
OUT
Voltage applied at VOUT terminal 2.1 12.6 26 V
of J2
Supply current Maximum input current 0 8 A
Charge current, I
chrg
Battery charge current 0 2 8 A For charge current above 2 A, replace R6
and L1 with high-current rating
components
Operating junction temperature range, T
J
0 125 °C
The bq24650EVM board requires a regulated supply approximately 1 V minimum above the regulated
voltage of the battery pack to a maximum input voltage of 28 Vdc. The charge voltage is programmed via
a resistor divider from the battery to ground, with the midpoint tied to the VFB pin.
R13 and R15 can be changed to regulate output between approximately 2.1 V to 26 V.
(1)
It is set at 12.6 Vdc from the factory.
A solar panel has a unique point on the V-I or V-P curve, called the maximum power point (MPP), at
which the entire photovoltaic (PV) system operates with maximum efficiency and produces its maximum
output power. The constant voltage algorithm is the simplest maximum power point tracking (MPPT)
method. The bq24650 automatically reduces charge current, so the maximum power point is maintained
for maximum efficiency.
If the solar panel or other input source cannot provide the total power of the system and bq24650 charger,
the input voltage drops. Once the voltage sensed on the MPPSET pin drops below 1.2 V, the charger
maintains the input voltage by reducing the charge current.
(2)
It is set at 17.8 Vdc from the factory.
3 SLUU444A – August 2010 – Revised October 2010 bq24650EVM Synchronous, Switch-Mode, Battery Charge Controller for Solar
Power
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