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Número de pieza | APW7207 | |
Descripción | Step-Up Converter | |
Fabricantes | ANPEC | |
Logotipo | ||
Hay una vista previa y un enlace de descarga de APW7207 (archivo pdf) en la parte inferior de esta página. Total 18 Páginas | ||
No Preview Available ! APW7207/A
1MHz, High-Efficiency, Step-Up Converter for White LEDs
Features
General Description
• Wide Input Voltage from 2.5V to 6V
The APW7207/A is a current-mode and fixed frequency
• 0.2V Reference Voltage
• Fixed 1MHz Switching Frequency
boost converter with an integrated N-FET to drive up to 10
white LEDs in series.
The series connection allows the LED current to be iden-
• High Efficiency up to 88%
tical for uniform brightness. Its low on-resistance of N-
• 100Hz to 200kHz PWM Brightness Control Fre- FET and feedback voltage reduces power loss and
achieves high efficiency. Fast 1MHz current-mode PWM
quency
operation is available for input and output capacitors and
• Open-LED Protection
a small inductor while minimizing ripple on the input
• Under-Voltage Lockout Protection
• Over-Temperature Protection
supply. The OVP pin monitors the output voltage and stops
switching if exceeds the over-voltage threshold. An inter-
nal soft-start circuit eliminates the inrush current during
• <1µA Quiescent Current During Shutdown
start-up.
• TSOT-23-6A and TDFN2x2-8 Packages
• Lead Free and Green Devices Available
The APW7207/A also integrates under-voltage lockout,
over-temperature protection, and current limit circuits.
The APW7207/A is available in TSOT-23-6A and TDFN2x2-
(RoHS Compliant)
8 packages.
Applications
Pin Configuration
• White LED Display Backlighting
• Cell Phone and Smart Phone
• PDA, PMP, and MP3
• Digital Camera
Simplified Application Circuit
VIN
C1
2.2µF
OFF ON
L1
22µH
VIN LX
GND OVP
EN FB
VOUT
C2
1µF Up tp 10
WLEDs
R1
10Ω
LX 1
GND 2
FB 3
6 VIN
5 OVP
4 EN
TSOT-23-6A
(Top View)
GND 1
VIN 2
OVP 3
EN 4
8 LX
7 NC
6 GND
5 FB
TDFN 2x2-8
Top View
ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and
advise customers to obtain the latest version of relevant information to verify before placing orders.
Copyright © ANPEC Electronics Corp.
Rev. A.7 - Nov., 2012
1
www.anpec.com.tw
1 page APW7207/A
Operating Waveforms
(Refer to the application circuit in the section “Typical Application Circuits”, VIN=3.6V, TA=25oC, 10WLEDs unless otherwise
specified )
VEN
VOUT, 10V/Div
IIN, 0.2A/Div
10WLEDs, L=22µH, VIN=3.6V, ILED=20mA
VLX, 20V/Div, DC
VOUT, 100mV/Div, AC
IL, 0.2A/Div
10WLEDs, L=22µH, VIN=3.6V, ILED=20mA
VOUT, 10V/Div
Copyright © ANPEC Electronics Corp.
Rev. A.7 - Nov., 2012
5
www.anpec.com.tw
5 Page APW7207/A
Application Information (Cont.)
Layout Consideration
For all switching power supplies, the layout is an impor-
tant step in the design; especially at high peak currents
and switching frequencies. If the layout is not carefully
done, the regulator might show noise problems and duty
cycle jitter.
1. The input capacitor should be placed close to the VIN
and GND. Connecting the capacitor with VIN and GND
pins by short and wide tracks without using any vias for
filtering and minimizing the input voltage ripple.
2. The inductor should be placed as close as possible to
the LX pin to minimize length of the copper tracks as
well as the noise coupling into other circuits.
3. Since the feedback pin and network is a high imped-
ance circuit, the feedback network should be routed
away from the inductor. The feedback pin and feed-
back network should be shielded with a ground plane
or track to minimize noise coupling into this circuit.
4. A star ground connection or ground plane minimizes
ground shifts and noise is recommended.
Via To OVP
To Anode of
WLEDs
VOVP D1
LX
From Cathod of
WLEDs
R1
L1
C1
VIN
Via To VOVP
VEN
Refer to Fig. 1
VIN L1
Via To VOVP
VEN
C1
1
2
3
4
D1
VOVP
8 LX
7 NC
6 GND
5
FB
R1
To Anode of
WLEDs
From Cathod of
WLEDs
Fig 4. APW7207/A Layout Suggestion
Copyright © ANPEC Electronics Corp.
Rev. A.7 - Nov., 2012
11
www.anpec.com.tw
11 Page |
Páginas | Total 18 Páginas | |
PDF Descargar | [ Datasheet APW7207.PDF ] |
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