SC604A
POWER MANAGEMENT
Block Diagram
ILED4
13
ILED3
14
ILED2
15
ILED1
16
C2+
11
C1+
8
C1-
9
C2-
10
Current Brightness Control
VOUT
VIN
6
7
GND
12
TM
mAhXLife Fractional Charge Pump
[1x, 1.5x, 2x]
Current Sense FETs
and Amplifier(s)
Current Set Detect
ISET
5
250kHz
Oscillator
& Delay Clk
Ouput Selection
Logic
Mode Select
[1x, 1.5x, 2x
Startup, Shutdown]
1.22V Bandgap
Voltage
EN
1
Schmitt Buffer
Schmitt Buffer
Schmitt Buffer
Schmitt Buffer
CTRL0
CTRL1
CTRL2
2
3
4
Table 1 - LED Enable Logic
Control Inputs
(1)
Output Status
CTRL2
CTRL1
CTRL0
LED4
OFF
OFF
OFF
ON
LED3
OFF
OFF
ON
LED2
OFF
ON
LED1
ON
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
OFF
OFF
OFF
ON
OFF
OFF
ON
OFF
OFF
ON
OFF
OFF
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
OFF
Notes:
(1) The sequencing of Enable and logic state CTRL{2,1,0} = [1, 1, 1] will affect quiescent state current. IQ = 100µA if Enable transitions high before
CTRL{2,1,0} transitions to [1, 1, 1]. IQ = 400µA if Enable transitions high after CTRL{2,1,0} transitions to [1, 1, 1]. If Enable = high and CTRL{2,1,0}= [1, 1,
1] is to be used for an extended period of time, it is recommended that Enable = High when change to the [1, 1, 1] state to achieve the lower IQ level.
2005 Semtech Corp.
www.semtech.com
6
SEMTECH [ SEMTECH CORPORATION ]
