[AP2071AEN]

MS1607-E-00

- 17 -

2014/03

The AP2071AEN can detect LED temperature with a NTC thermistor (Negative Temperature Coefficient

Thermistor) which is connected to the NTC pin. The current which flows to the NTC thermistor is 35µA.

Protection

Conditions

Device Status

Recovering Condition

LED1~4 over

temperature

protection (Note 8)

NTC pin voltage

< setting voltage

(DET[2:0])

All circuits are powered down

Address= “08H”, LEDTHRM

bit= “1”

Set LED1~4= “0” again

or EN pin= “off”-> “ON”

again

Note 8. The parasitic capacitor of NTC pin should be lower 50pF.

Example）

NTC thermistor： NCP15WM154 (150k @25C、B constant=4582, 1005 size, Murata)

NCP15WM224 (220k @25C, B constant=4582, 1005 size, Murata)

Formula: R=Ro*exp(B*(1/T-1/To))

(R: The value in the case of ambit temperature T(k)) (K: kelvin)

(Ro: The value in the case of ambit temperature To(k))

Detection Voltage (V) @typ

(set by resistor)

0.60

0.67

0.74

0.81

0.88

0.95

1.02

Detection Resistor (kΩ)

17.1

19.1

21.1

23.1

25.1

27.1

29.1

Detection Temperature (C)

(in the case of using 150kohm)

74

71

69

66

64

62

61

Detection Temperature (C)

(in the case of using 220kohm)

84

82

79

76

74

72

70

Temperature (C)

In the case of using 150kohm

In the case of using 220kohm