|
|
PDF TC3827 Data sheet ( Hoja de datos )
| Número de pieza | TC3827 | |
| Descripción | Lithium-Ion Battery Charger | |
| Fabricantes | Microchip | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de TC3827 (archivo pdf) en la parte inferior de esta página. Total 10 Páginas | ||
|
No Preview Available !
TC3827
Lithium-Ion Battery Charger
FEATURES
s Low Power Dissipation
s Shutdown Current: 1µA (Typical)
s Space-Saving 8-Pin MSOP Package
s No Inductor Required
s 1% Overall System Accuracy
s Charge Current Monitor Output
s Charge Status Indicator Output
s Foldback Current Limiting
s –20°C to +85°C Ambient Operating
Temperature Range
TYPICAL APPLICATIONS
s PDAs
s Cradle Chargers
s Li-Ion Battery Chargers
s Desktop Computers
s Hand-Held Instruments
s Cellular Telephones
s Battery Operated Devices
s Self-Charging Battery Packs
PIN CONFIGURATION
8-Pin MSOP
SHDN 1
GND 2
MODE 3
IMON 4
TC3827
8 VIN
7 VSNS
6 VDRV
5 VOUT
TYPICAL APPLICATION CIRCUIT
+5 VIN
LED
MODE
IMON
SHDN
Controller
RSENSE
NDP6020P
PMOS
10µF
VIN VSNS
VDRV
VOUT
MODE TC3827
IMON
SHDN
GND
GENERAL DESCRIPTION
The TC3827 is a battery charger controller for a single
cell Li-Ion battery. Using an external PMOS transistor, safe
and fast charging of a single Li-Ion cell is accomplished.
Features include over-current foldback, charge current
monitor, and charge status LED indicator output. An overall
system accuracy of 1% ensures that the cell capacity is fully
utilized without cycle life degradation. An external resistor
sets charge current.
The TC3827 operates with an input voltage range from
4.5V to 5.5V. It is specified over the ambient operating
temperature range of –20°C to +85°C and is available in a
space-saving 8-Pin MSOP.
ORDERING INFORMATION
Part No.
TC3827-4.1VUA
TC3827-4.2VUA
Package
8-Pin MSOP
8-Pin MSOP
Temperature
Range
–20°C to +85°C
–20°C to +85°C
FUNCTIONAL BLOCK DIAGRAM
VIN
VSNS
+
C/A
–
GND
VOUT
VREF
+
E/A
–
+
E/A
–
SHDN
+
22µF
Li-Ion –
K IMON
CONTROL
BLOCK
VDRV
MODE
TC3827
Figure 1. TC3827 Typical Application Circuit
© 2001 Microchip Technology Inc. DS21558A
TC3827-2 12/12/00
Free Datasheet http://www.datasheet4u.com/
1 page  
Lithium-Ion Battery Charger
TC3827
control loop changes from current limiting to voltage regula-
tion. If an external micro-controller determines battery con-
ditions are unsafe for charge it can toggle the shutdown pin
low and interrupt the charge cycle. Otherwise, once the pre-
determined cell voltage is reached the TC3827 shifts into a
constant-voltage mode (linear regulation) and a variable
charge current is applied as required to maintain the battery
cell voltage to within 1% accuracy of the cell voltage set-
point.
IMON – Charge Current Status
The IMON pin provides an output voltage that is propor-
tional to the battery charging current . It is an amplified
version of the sense resistor voltage drop that the current
loop uses to control the PMOS device. This voltage signal
can be applied to the input of an A/D Converter and used by
a controller to display information about the state of the
battery or charge current profile.
Higher Current Option
The current sense resistor for the circuit shown in
Figure 1 is calculated by: RSENSE = VCS /IMAX .
Where VCS is the current limit threshold voltage of
40mV to 75mV, 50mV typical. If IMAX = 1A is desired,
RSENSE = 50mΩ.
Pre-regulated Input Voltage (5V ± 0%)
For this application, the required θJA thermal imped-
ance is calculated as follows:
if:
then:
the PMOS data sheet allows a max
junction temperature of TJMAX = 150°C,
at 50°C ambient with convection
cooling, the maximum allowed
junction temperature rise is:
MODE – Charge Mode Status LED
The MODE pin indicates the battery charging mode. An
LED can be connected to the MODE for a visible indicator.
Alternatively, a pull-up resistor (typically 100kΩ) from the
interfacing logic supply to MODE provides a logic-level
output. The MODE pin will toggle LOW and the LED will
illuminate when the charger is in the current limited mode.
The MODE pin toggles to a high impedance state and the
LED will be off during constant-voltage mode charging or if
the battery is not connected. The MODE pin toggles at a
VOUT of VREG, typically.
APPLICATION CIRCUIT DESIGN
Due to the low efficiency of Linear Regulator Charging,
the most important factors are thermal design and cost,
which is a direct function of the input voltage, output current
and thermal impedance between the PMOS and the ambi-
ent cooling air. The worst-case situation is when the battery
is shorted since the PMOS has to dissipate the maximum
power. A tradeoff must be made between the charge cur-
rent, cost and thermal requirements of the charger. Higher
current requires a larger PMOS with more effective heat
dissipation leading to a more expensive design. Lowering
the charge current reduces cost by lowering the size of the
PMOS, possibly allowing a smaller package such as 6-Pin
SOT. The following designs consider both options.
TJMAX – TAMAX = 150°C – 50°C = 100°C.
θJA = ∆T/(IOx k x VIN) = 100/(1 x 0.46 x 5.5)
= 39.5 °C/W
This k factor is: k = ISC/IMAX ≈ 0.46.
This thermal impedance can be realized using the
transistor shown in Figure 1 when mouted to a heat sink.
The θSA or thermal impedance of a suitable heatsink is
calculated below:
θSA ≤ (θJA – θJC – θCS) = 39.5 – 2.5 – 0.3 = 36.7°C/W
Where the θJC, or junction-to-case thermal impedance
is for the PMOS from the PMOS data sheet. A low cost
heatsink is Thermalloy type PF430, with a θSA = +25.3°C/W.
© 2001 Microchip Technology Inc. DS21558A
5
TC3827-2 12/12/00
Free Datasheet http://www.datasheet4u.com/
5 Page | ||
| Páginas | Total 10 Páginas | |
| PDF Descargar | [ Datasheet TC3827.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| TC3827 | Lithium-Ion Battery Charger | Microchip |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |