T6331A

tm
TE
CH
T6331A
Boost or SEPIC DC-DC Controller
FEATURES
GENERAL DESCRIPTION
• Wide Input Voltage Range: 2.7V to 5.5V
• Boost or SEPIC DC-DC Mode Controller
• VDD Under Voltage Lockout
• Build in over voltage Protect
• SOP-8 and SOT-23-6 Lead-free Package
The T6331A are integrated, high-efficiency
white or RGB LED drivers. They are designed
for LED lighting applications.
TheT6331A it can be used with boost or buckboost (SEPIC) topologies. The constantcurrent outputs are single resistor or PWM
programmable and the LED current can be
adjusted.
The T6331A is available in SOP-8 and SOT23-6 Lead-free package.
Applications
• Handheld Electronics
• MR-16
• Lighting Divice
PART NUMBER EXAMPLES
PART NO.
TM Technology, Inc. reserves the right
to change products or specifications without notice.
P. 1
PACKAGE
T6331A-AXG
SOT-23
T6331A-ADG
SOP-8
Publication Date: JAN. 2010
Revision: A
tm
TE
CH
T6331A
PIN ARRANGEMENT(Top view)
FB
VDD
ADJ
1
A D JO F F
4
2
3
8
7
LX
VSS
6
CS
5
OVP
LX
VSS
CS
SOP-8
1
2
3
6
5
4
FB
VDD
ADJ
SOT-23-6
PIN DESCRIPTION
SYMBOL
SOP-8
SOT-23-6
FB
VDD
ADJ
ADJOFF
OVP
CS
VSS
LX
1
2
3
4
5
6
7
8
6
5
4
3
2
1
DESCRIPTION
Voltage Feed Back pin.
Power Supply
Dimming pin
ADJ-pin turn Off Voltage Level set pin
Over Voltage Protect
Switch Current Sense
Ground
Connected to external MOSFET gate pin
TM Technology, Inc. reserves the right
to change products or specifications without notice.
P. 2
Publication Date: JAN. 2010
Revision: A
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T6331A
ABSOLUTE MAXIMUM RATINGS
Parameter
Voltage on any pin relative to GND
Symbol
VIN
Value
-0.3 to 7
Unit
V
TA
-40 to +85
°C
TLEAD
300
°C
TS
-65 to +150
°C
SOT-23
350
SOP-8
800
Operating Temperature Rang
Maximum Soldering Temperature (at leads, 10 sec)
Storage Temperature Rang
Continuous Power Dissipation ( TA = +70°C )
mW
Electrical Characteristics
(TA = -40 to 85°C unless otherwise noted. Typical values are at TA =25°C, VDD =5V)
Symbol
Description
VDD Operating voltage range
Conditions
power supply input
Min. Typ. Max
2.7
5.5
Unit
V
2.7
V
VUVLO VDD Under Voltage Lockout
VFB
FB pin voltage
0.15
V
tSW
Switching Frequency
500
KHz
IDD
Switch Off Current
300
uA
IOFF
ADJ turn off Current
ILED
LED sink current
ILSD
LED leakage current in
shutdown
ICS
CS pin Peak Switch Current
VADJ
External control voltage range
VADJOFF Vadj OFF DC level (floating)
VOVP
OVP Protect Reference Level
30
VDD = 2.7V~5.5V
RFB=1 ohm
150
mA
RFB=0.214 ohm
700
mA
1
VLED= 3.3V, VDD=0V, TA=+25°C
2
Limit= 0.1/Rcs , Rcs=0.05 ohm
On ADJ pin for DC brightness control
0
External resistor level
=3.35uA Radjoff ,
Over reference level to turn off
Duty cycle range of PWM signal
PWM frequency>1KHz
applied to ADJ pin during high
DPWMH frequency PWM dimming mode PWM amplitude = VREF
Measured on ADJ pin
Brightness control range
TM Technology, Inc. reserves the right
to change products or specifications without notice.
P. 3
uA
uA
A
1.2
V
0.2
V
1.2
V
0.16
1
6:1
Publication Date: JAN. 2010
Revision: A
tm
TE
CH
T6331A
Functional Description
The T6331A are integrated, high-efficiency white or RGB LED drivers. They are designed for
LED lighting applications.
TheT6331A it can be used with boost or buck-boost (SEPIC) topologies. The constant-current
outputs are single resistor or PWM programmable and the LED current can be adjusted.
Setting the Output Current
FB controls the LED bias current. greater than the current flowing into RSET. Set the output current as
follows:
ILED = (0.15V / RFB )
Output current adjustment by external DC control voltage
The ADJ pin can be driven by an external dc voltage (VADJ), as shown, to adjust the output current
to a value above or below the nominal average value defined by RFB.
ADJ
+
T6331A
GN D
DC
GND
The nominal average output current in this case is given by:
IOUTdc = (VADJ /1.2) x (0.15V / RFB), [for 0 < VADJ <1.2V]
Note that 100% brightness setting corresponds to VADJ ≧ VREF. When driving the ADJ pin above
1.2V.
Output current adjustment by PWM control
Directly driving ADJ input
A Pulse Width Modulated (PWM) signal with duty cycle DPWM can be applied to the ADJ pin, as
shown below, to adjust the output current to a value above or below the nominal average value set
by resistor RFB:
V ADJ
0V
PW M
ADJ
T6331A
GN D
TM Technology, Inc. reserves the right
to change products or specifications without notice.
P. 4
Publication Date: JAN. 2010
Revision: A
tm
TE
CH
T6331A
Driving the ADJ input from a microcontroller
Another possibility is to drive the device from the open drain output of a microcontroller. The
diagram below shows one method of doing this:
M CU
AD J
T 6331A
GND
If the NMOS transistor within the microcontroller has high Drain / Source capacitance, this
arrangement can inject a negative spike into ADJ input of the T6331A and cause erratic operation
but the addition of a Schottky clamp diode (cathode to ADJ) to ground and inclusion of a series
resistor (10K) will prevent this. See the section on PWM dimming for more details of the various
modes of control using high frequency and low frequency PWM signals.
Set ADJ Turn OFF Level
ADJOFF pin may set when dimming with ADJ turn off output minimum level. If usually ADJOFF
pin floating, then the ADJ internal default turn off output reference level is 0.2V, when therefore the
ADJ dimming DC signal level is lower than 0.2V, then the output current will turn off. Therefore
may simple a ADJOFF external connection resistance to the GND, the ADJ turn off output level to
the simple application change.
Set the VADJ OFF DC level as follows:
VADJ OFF DC level = 3.35uA * RADJOFF
Over Voltage Protection
Since T6331A is configured as current source, the output voltage rises as the output impedance
increases or output is open-circuit (e.g. fault LED). The output voltage may exceed the maximum
voltage rating of the internal and external main switch. An overvoltage protection circuit is
integrated to prevent the main switch from burning. When the output voltage exceeds the OVP
threshold voltage, the main switch is turned off. It remains off until the output voltage falls below
the OVP threshold voltage. The step-up converter continues normal operation as long as the output
voltage is under the OVP threshold. OVP pin reference voltage level is 1.2V.
Peak Switch current Protection
If external connection MOSFET the instantaneous switch current is large, over MOSFET the
specification, then MOSFET will burn out, to prevent the instantaneous switch the large current,
may use CS-pin to make the protection. CS pin Peak Switch Current Limit= 0.1/Rcs
TM Technology, Inc. reserves the right
to change products or specifications without notice.
P. 5
Publication Date: JAN. 2010
Revision: A
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T6331A
TYPICAL APPLICATION CIRCUITS
L1
47uH
V IN
C3
2.2uF
C2
10uF
D1
L2
47uH
Rz
VDD
LX
Q1
LED
Cin
CS
Zener
RCS
dimming
ADJ
FB
ADJOFF
VSS OVP
R ADJOFF
R OVP1
R1
R OVP2
Note: *R1 value is RFB=0.15V/ ILED
Typical Application Circuit
TM Technology, Inc. reserves the right
to change products or specifications without notice.
P. 6
Publication Date: JAN. 2010
Revision: A
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T6331A
PACKAGE DIMENSIONS
8-LEAD SOP
B
B1
K
T h e rm a l P a d *
J
A1
C1
A
C
C2
F
D
Symbol
A
A1
B
B1
C
C1
C2
D
E
F
J
K
H
Min.
5.70
3.75
1.35
0.10
0.31
0.30
0.10
Dimension in mm
Typ.
6.00
3.95
1.27
1.55
0.41
0.50
0.15
2.23 REF
2.97 REF
0~8°
E
H
Max.
6.30
4.10
5.13
1.80
1.75
0.25
0.51
0.70
0.25
Min.
0.224
0.148
0.052
0.001
0.012
0.012
0.004
Dimension in inch
Typ.
0.236
0.156
0.050
0.061
0.016
0.020
0.006
0.088 REF
0.117 REF
0~8°
Max.
0.248
0.164
0.202
0.071
0.069
0.004
0.020
0.028
0.010
*Note :
The thermal pad on the IC’s bottom has to be mounted on the copper foil.
To eliminate the noise influence, the thermal pad is suggested to be connected to GND on PCB.
In addition, desired thermal conductivity will be improved, if a heat-conducting copper foil on
PCB is soldered with thermal pad. The thermal pad enhances the power dissipation. As a result, a
large amount of current can be sunk safely in one package.
TM Technology, Inc. reserves the right
to change products or specifications without notice.
P. 7
Publication Date: JAN. 2010
Revision: A
tm
TE
CH
T6331A
PACKAGE DIMENSIONS
SOT23-6
B
B 1
B 2
A 1
C 1
A
C
C 2
F
D
I
Symbol
A
A1
B
B1
B2
C
C1
C2
D
E
F
G
H
I
Min.
2.60
1.40
2.70
0.95
0.90
0
0.30
0.08
Dimension in mm
Typ.
2.80
1.575
2.85
1.90(BSC)
0.95(BSC)
1.20
1.10
0.075
0.40
0.45
0.15
0.60(REF)
H
Max.
3.00
1.60
3.00
Min.
0.102
0.055
0.106
1.45
1.30
0.150
0.037
0.035
0
0.60
0.22
0.012
0.003
G
Dimension in inch
Typ.
0.110
0.062
0.112
0.075(BSC)
0.037(BSC)
0.047
0.043
0.003
0.015
0.018
0.006
Max.
0.118
0.063
0.118
0.057
0.051
0.06
0.023
0.009
0~8°
5~15°
5~15°
TM Technology, Inc. reserves the right
to change products or specifications without notice.
E
P. 8
Publication Date: JAN. 2010
Revision: A