Linear Technology DC1210A, Quick Start Manual

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LTC4090
1
DESCRIPTION
Demonstration circuit DC1210A is high voltage sw itching
buck regulator, U SB Pow erpath controller and Li-Ion bat-
tery charger. It is based on the LTC4090 and provides
the follow ing functions: 2A buck regulator w ith 6-38V (60V max) input range and
w ith output voltage tracking battery voltage, full featured
battery charger w ith 4.2V float, U SB pow er manager that
ensures compliance w ith the U SB pow er specification
and a pow er path manager for the battery.
PERF ORM A NCE SU M M A RY
Specifications are at TA = 25°C
SYM BOL PARAM ETER CONDITIONS M IN TYP M AX UNITS
V
IN
Input Supply Range - USB 4.35 5.5 V
V
HVIN
Input Supply Range - HVIN (W ithstands up to 60V w ithout damage) 6 60 V
V
OVLO
HVIN Overvoltage Lockout Threshold 38 41.5 45 V
Battery Charger
I
CH G
Charging current V
HVIN
= 12V, V
BAT
= 3.6V , R4 = 71.5k
Ω
650 700 750 mA
V
FLOAT
V
BAT
Regulated Output Voltage I
BAT
= 2mA 4.165 4.200 4.235 V
I
TRKL
Trickle Charge Current V
BAT
= 2V 49 70 84 mA
∆
V
RECH R G
Recharge threshold Threshold Voltage Relative to V
FLOAT
-65 -100 -135 mV
Input Current
I
LIM
Input current 100mA mode HPW R = 0V, R3 = 2.10k
Ω
86 93 105 mA
I
LIM
Input Current 500mA mode HPW R = 5V, R3 = 2.10k
Ω
452 476 500 mA
I
IN(SUSP)
Suspend M ode Input Current SU SP = 5V 50 100 µA
OPERA TING PRINCIPL ES
Demo board DC1210A is based on the LTC4090. This
chip manages the pow er supplies that w ould be typical
for a U SB pow ered device. Pow er is input from either the
U SB cable or from a high voltage ( 6V-38V) H VIN input
to an intermediate voltage bus.
The intermediate voltage bus is pow ered from U SB or
H VIN w hen available, and from the battery via an ideal
diode. The battery charger is a CC/CV timer terminated
type capable of charge currents up to 1.5A
The H VIN input has overvoltage protection to 60V. The
2A buck regulator connected to H VIN operates at 800kHz
and its output voltage is regulated in the range 3.45V to
4.6V, tracking the battery voltage and typically 0.3V
higher to allow most efficient charging.
DEMO C IR C U IT DC 1 2 1 0 A
Q u ic k S ta rt G u id e
L T C 4 0 9 0
U S B P o w e r Ma n a g e r w ith 2 A
H ig h V o lta g e B u c k R e g u la to r
B u c k Io n / P o ly m e r C h a rg e r