S-8813 Datasheet, PDF (15/29 Pages) Seiko Instruments Inc – 3-CHANNEL WHITE LED DRIVER IC (CHARGE PUMP IC WITH BUILT-IN CONSTANT-CURRENT CIRCUIT)

3-CHANNEL WHITE LED DRIVER IC (CHARGE PUMP IC WITH BUILT-IN CONSTANT-CURRENT CIRCUIT)
Rev.2.1_00
S-8813 Series
3. Regulating Luminance Circuit via PWM control signal (It corresponds only to S-881300CPE.)
White
LED
0.22 μF
IOUT1
ON/ OFF
IOUT2
RISET
S-881300
CPE
IOUT3
CPOUT
C+
VIN
C−
GND
Control signal
R1^*1=5.6 kΩ to 20 kΩ
PWM
control signal
4.7 μF
10 μF
Figure 17 Application Circuit 3 (S-881300CPE)
(1) When f_PWM=1.0 kHz
V_IH=2.0 V, V_IN=3.0 V, f_PWM=1.0 kHz, Ta=25°C
20
16
R₁^*1=5.6 kΩ, R_Z^*2=0 Ω
R₁^*1=20 kΩ, R_Z^*2=0 Ω
12
8
4
0
0 20 40 60 80 100
PWM Duty Ratio [%]
Figure 18 I_OUT-PWM Duty Ratio Dependence 1
(R_1*1 Dependence)
V_IH=2.0 V, R₁^*1=5.6 kΩ, R_Z^*2=0 Ω,
f_PWM=1.0 kHz, Ta=25°C
20
V_IN=3.0 V
16
V_IN=3.5 V
12
V_IN=4.5 V
8
4
0
0 20 40 60 80 100
PWM Duty Ratio [%]
Figure 19 I_OUT-PWM Duty Ratio Dependence 1
(V_IN Dependence)
V_IH=2.0 V, R₁^*1=5.6 kΩ, R_Z^*2=0 Ω,
V_IN=3.0 V, Ta=25°C
20
f_PWM=100 Hz
16
f_PWM=1.0 kHz
12
8
4
0
0 20 40 60 80 100
PWM Duty Ratio [%]
Figure 20 I_OUT-PWM Duty Ratio Dependence 1
(f_PWM Dependence)
VIH=2.0 V, R1^*1=5.6 kΩ, RZ^*2=0 Ω,
VIN=3.0 V, fPWM=1.0 kHz
20
Temp.=−40°C
16
Temp.=25°C
12
Temp.=85°C
8
4
0
0 20 40 60 80 100
PWM Duty Ratio [%]
Figure 21 I_OUT-PWM Duty Ratio Dependence 1
(Temp. Dependence)
*1. Current setting resistance
*2. The output impedance of the PWM output control signal source when the PWM control signal is “L”
Seiko Instruments Inc.
15