LTC4160EUDC#PBF Linear Technology, LTC4160EUDC#PBF Datasheet - Page 13

• Manufacturer Part Number: LTC4160EUDC#PBF
• Description: IC, BATT CHRG, Li-Ion, Li-Polymer, 1.2A, QFN20
• Manufacturer: Linear Technology

Specifications of LTC4160EUDC#PBF

• Battery Type: Li-Ion, Li-Polymer
• Input Voltage: 5.5V
• Battery Charge Voltage: 4.2V
• Charge Current Max: 1.2A
• Battery Ic Case Style: QFN
• No. Of Pins: 20
• No. Of Series Cells: 1
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

OPERATION
Introduction
The LTC4160/LTC4160-1 are high efficiency bidirectional
switching power managers and Li-Ion/Polymer battery
chargers designed to make optimal use of the power
available while minimizing power dissipation and easing
thermal budgeting constraints. The innovative PowerPath
architecture ensures that the end product application is
powered immediately after external voltage is applied,
even with a completely dead battery, by prioritizing power
to the end product.
When acting as a step-down converter, the LTC4160/
LTC4160-1’s bidirectional switching regulator takes power
from USB, wall adapters, or other 5V sources and provides
power to the end product application and efficiently charges
the battery using Bat-Track. Because power is conserved,
the LTC4160/LTC4160-1 allow the load current on V
exceed the current drawn by the USB port, making maxi-
mum use of the allowable USB power for battery charging.
For USB compatibility, the switching regulator includes
a precision average input current limit. The bidirectional
switching regulator and battery charger communicate to
ensure that the average input current never exceeds the
USB specifications.
In addition, the bidirectional switching regulator can also
operate as a 5V synchronous step-up converter, taking
power from V
without the need for any additional external components.
This enables systems with USB dual-role transceivers to
function as USB On-The-Go dual-role devices. True output
disconnect and average output current limit features are
included for short circuit protection.
The LTC4160/LTC4160-1 contain both an internal 180mΩ
ideal diode as well as an ideal diode controller for use
with an external P-channel MOSFET. The ideal diodes
from BAT to V
available to V
power at V
An always-on LDO provides a regulated 3.3V from avail-
able power at V
this LDO will be on at all times and can be used to supply
up to 20mA.
BUS
OUT
OUT
.
OUT
OUT
guarantee that ample power is always
even if there is insufficient or absent
. Drawing very little quiescent current,
and delivering up to 500mA to V
OUT
BUS
to
The LTC4160/LTC4160-1 also feature an overvoltage pro-
tection circuit which is designed to work with an external
N-channel MOSFET to prevent damage to their inputs
caused by accidental application of high voltage.
Finally, to prevent battery drain when a device is con-
nected to a suspended USB port, an LDO from V
V
product application.
Bidirectional PowerPath Switching Regulator –
Step-Down Mode
The power delivered from V
a 2.25MHz constant frequency bidirectional switching
regulator in step-down mode. V
of the external load and the battery charger. To meet the
maximum USB load specification, the switching regulator
contains a measurement and control system that ensures
that the average input current remains below the level
programmed at CLPROG.
If the combined load does not cause the switching regu-
lator to reach the programmed input current limit, V
will track approximately 0.3V above the battery voltage.
By keeping the voltage across the battery charger at this
low level, power lost to the battery charger is minimized.
Figure 1 shows the power flow in step-down mode.
If the combined external load plus battery charge current
is large enough to cause the switching regulator to reach
the programmed input current limit, the battery charger
will reduce its charge current by precisely the amount
necessary to enable the external load to be satisfied. Even
if the battery charge current is programmed to exceed the
allowable USB current, the USB specification for average
input current will not be violated; the battery charger will
reduce its current as needed. Furthermore, if the load cur-
rent at V
load current will be drawn from the battery via the ideal
diode(s) even when the battery charger is enabled.
The current out of CLPROG is a precise fraction of the V
current. When a programming resistor and an averaging
capacitor are connected from CLPROG to GND, the volt-
age on CLPROG represents the average input current of
the switching regulator. As the input current approaches
OUT
provides low power USB suspend current to the end
OUT
exceeds the programmed power from V
LTC4160/LTC4160-1
BUS
OUT
to V
drives the combination
OUT
is controlled by
13
BUS
41601fa
BUS
OUT
BUS
to
,