＜MFT＞

RT8Ｈ164Ｃ

LED driver circuit with UVLODESCRIPTION
RT8H164C is composed by NPN transistors,PNP transistors

Unit：mmOUTLINE DRAWING

2.8and resistors.It can miniaturization of a set and reduceparts or time necessary for completion.

0.65

1.5

0.65

adjusted by comparing it with the built-in voltage of 0.2V.

③

The light intensity of the LED can be adjusted by inputting⑥④0.332.8

detected by the CSP terminal, and the LED current is①164

rise of the resistor RCS connected to he GND side is

0.95 0.95

RT8H164C constitutes the LED driver circuit. The voltage

0.81

It is also has a built-in UVLO function to prevent
malfunction at 4V or less and thermal shutdown function.

0.12

The off-time can be set by connecting an external resistor
and capacitor to the CT terminal.

0～0.1

1.1

a signal to the DIM terminal.

PIN CONFIGURATIONFEATURES●Miniaturization of a set.

①OUT

●External setting of LED light intensity is possible

②VCC

⑤GND

③DIM

④CT

with the DIM terminal.

⑥CSP●External setting of a switch-off time is possible
with the switch-off time setting terminal (CT).
●Built-on UVLO function and thermal shutdown function.
APPLICATION●LED driver circuit
BLOCK DIAGRAM
VCC
8.0V

Oscillator

CT

Overheatprotection

UVLO

OUT

OSC Comp
CSP

S

QR

Latch circuit(R has priority)
GND

CS Comp

0.20V

DIM

240423

＜MFT＞

RT8Ｈ164Ｃ

LED driver circuit with UVLO
ABSOLUTE MAXIMUM RATINGS (Ta＝25℃)
SymbolParameter
Conditions
Supply voltage
VCC
IOUT
Output current
PdInternal power dissipation
Kθ
Thermal deratingTa≧25℃
Tj
Junction temperature
Tstg
Storage temperature(keep dry)ToprOperating temperature(keep dry)Ratings
40±302001.6
150－40～150－20～85

Unit
VmAmW
mW/℃℃
℃℃

RECOMMENDED OPERATING RANGE
SymbolParameter

VCC
fRatings

Unit

Min

Max

Supply voltage range

4.537

V

Frequency range

-200

kHz

ELECTRICAL CHARACTERISTIC (Ta=25℃,VCC=12V unless otherwise noted.)
Designed value
SymbolParameter
Test condition
Min
TypMaxUnit

VCC

Operating supply
voltage range

4.5

1237

V

VON

Operation start voltage

4.00

4.30

4.60

V

VOFF

Operation stop voltage

3.69

4.05

4.41

V

0.188

0.200

0.212

V

ICC1Circuit current1

CSP:2V, CT:0V

0.62

0.89

1.16mAICC2

Circuit current2

CSP:0V, CT:5V

0.56

0.80

1.04mAIBCSP

CSP bias current

CSP:0V/IM, CT:0V-300-120

0nA

VTHDIM DIM threshold voltage

CSP:0.3V, CT:5V

1.12

1.40

1.68

V

VTHCT1 CT threshold voltage 1

CSP:0V, CT:0V ⇒ SWEEP(L→H)/IM

2.60

3.10

3.60

V

1.55

1.85

2.15

V

5.60

7.00

8.40

V

0.60

0.75

0.90

V-

4.00

-us-170-℃

VTHCSP CSM threshold voltage

VTHCT2 CT threshold voltage 2VOSAT1 OUT saturation voltage 1
VOSAT2 OUT saturation voltage 2
TOOFF(※) Switch-off time
TSD(※)

CSP:0.3V
CT:VTHCT1 ⇒ SWEEP(H→L)/IM
CSP:0V,CT:0V, OUT:-5mA
CSP:0.3V,
CT:0V, OUT:5mA

RCT=47kΩ, CCT=330pF

Thermal shutdown

CHARACTERISTICS

THERMAL DERATING

200Pd[mW]

Power consumption

250

150
1005000255075100 125 150

Ambient temperrature Ta[℃]240423

＜MFT＞

RT8Ｈ164Ｃ

LED driver circuit with UVLOAPPLICATION CIRCUIT EXAMPLES

LD1CLDs

LED VF

D10.1uF

CVCC8.0V(About 6V)

12VVCC

LD..

47K

UVLO

L
330uH
NMOS1OUT

VL(on)=V − (VL(o )=V(OSC Comp)22)

CSP RNF

R

Latch circuit(R has priority)

CS Comp

0.20V

DIM

GND

2Ω

SQ

RCS

CT

Overheatprotection

CNF

CCT

330pF

RCT

Oscillator※RNF and CNF is low pass filter.
Please connect yhen you need it.

○Setting off-time (t off )The off-time is determined by the time when the charging voltage of the CT terminal resistor R CT
and the capacitor CCT reaches the upper limit of the CT terminal voltage (VCT(H) ) set inside the RT8H094C.
VCC − VCT L
t off = R CT ∙ CCT ∙ ln()
VCC − VCT H(VCT(H) ∶ CT terminal voltage (output HIGH), VCT(L) : CT terminal voltage (output LOW))○Setting on-time (t on )t on =L
VL(on)(I − Imin )Imin refers to the diode current just before the OUT terminal voltage turns from off to on.
The I and Imin arithmetic expressions are as follows.
※The accuracy of Iave is about ±7% only for product variations.
(When the constants of the external components are the above application circuit example.)
VL(off)
VL(off)
VCSPTH
I+IV
Iave = 2min = RCSM − 2L t off
I=Imin = I −t off
CSR CSL

TIMING CHART(It is based on the application circuit example)
CSM Voltage(≦0.2V)CSP Voltage

Threhold:About 3V

CT Voltage

Switch-off time

OUT Voltage

Diode current

240423

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Apr.2024