LP3952 Datasheet, PDF (9/44 Pages) National Semiconductor (TI) – 6-Channel Color LED Driver with Audio Synchronization

Magnetic Boost DC/DC Converter Electrical Characteristics
Symbol
Parameter
I_LOAD
Load Current
V_OUT
RDS_ON
f_boost
Output Voltage Accuracy
(FB Pin)
Output Voltage
(FB Pin)
Switch ON Resistance
PWM Mode Switching
Frequency
Frequency Accuracy
t_PULSE
t_STARTUP
I_{SW_MAX}
Switch Pulse Minimum
Width
Startup Time
SW Pin Current Limit
Conditions
3.0V ≤ V_IN
V_OUT = 5V
3.0V ≤ V_IN
V_OUT = 4V
3.0V ≤ V_IN ≤ V_OUT - 0.5
V_OUT = 5.0V
1 mA ≤ I_LOAD ≤ 300 mA
V_IN > 5V + V_(SCHOTTKY)
V_DD1,2 = 2.8V, I_SW = 0.5A
RT = 82 kΩ
freq_sel[2:0] = 1XX
2.7 ≤ VDDA ≤ 2.9
RT = 82 kΩ
no load
Boost startup from STANDBY
Min
Typ
Max Units
0
300
mA
0
400
−5
+5
%
V_IN–V_(SCHOTTKY)
V
0.4
0.8
Ω
2
MHz
−6
±3
+6
%
−9
+9
25
ns
10
ms
700
800
900
mA
550
950
BOOST STANDBY MODE
User can stop the Boost Converter operation by writing the
Enables register bit EN_BOOST low. When EN_BOOST is
written high, the converter starts for 10 ms in PFM mode and
then goes to PWM mode.
Boost Output Voltage Control
BOOST OUTPUT VOLTAGE CONTROL
User can control the boost output voltage by boost output 8-
bit register.
Boost Output [7:0]
Register 0DH
Boost Output
Voltage (typical)
Bin
Hex
0000 0000
00
4.00
0000 0001
01
4.25
0000 0011
03
4.40
0000 0111
07
4.55
0000 1111
0F
4.70
0001 1111
1F
4.85
0011 1111
3F
5.00 Default
0111 1111
7F
5.15
1111 1111
FF
5.30
BOOST FREQUENCY CONTROL
freq_sel[2:0]
1XX
01X
001
30023809
frequency
2.00 MHz
1.67 MHz
1.00 MHz
Register ‘boost freq’ (address 0EH). Register default value
after reset is 07H.
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