SSL2115X
Low-cost non-dimmable LED driver IC
Rev. 2 — 7 June 2012
Product data sheet
1. General description
The SSL2115X is a low-cost non-dimmable LED driver IC. It is designed to drive LEDs in
isolated flyback or non-isolated buck-boost topologies. The device includes a high-voltage
power switch and a circuit enabling start-up directly from the rectified mains voltage. It has
a good controlled output current.
2. Features and benefits
Compact solution with a small form factor and a low component count
Ease of integration
Primary side sensing (no optocoupler required)
True current source behavior:
LED current independent of mains voltage, LED voltage and temperature variation
LED current accuracy (10 %)
Line regulation:
3
% at 230 V
10
%
Load regulation:
3
% between 0.5
U
max
and 0.85
U
max
Efficiency up to 86 % depending on the application
Power Factor 0.6 or ~0.9 using valley fill
Low ripple current < 1 %
Internal protections:
OverTemperature Protection (OTP)
LED short protection (I
OUT
(0 V – V maximum) at a constant level)
LED open protection
UnderVoltage LockOut (UVLO)
Internal supply voltage generation enabling start-up from the rectified mains voltage
SO7 package
NXP Semiconductors
SSL2115X
Low-cost non-dimmable LED driver IC
3. Applications
SSL21151 is suitable for applications up to 5 W mains power
SSL21153 is suitable for applications up to 10 W mains power
SSL retrofit lamps (small-sized light bulbs or LED spots)
LED module, mains AC/DC converter (down-lights)
LED strings (retail displays)
4. Quick reference data
Table 1.
Symbol
V
CC
R
DSon
Quick reference data
Parameter
supply voltage
drain-source on-state
resistance
Conditions
operating range
SSL21151;
T
j
= 25
C
SSL21153;
T
j
= 25
C
f
sw(high)
I
M(DRAIN)
V
DRAIN
T
j
high switching frequency
peak current on pin
DRAIN
voltage on pin DRAIN
junction temperature
normal operation
SSL21151
SSL21153
Min
0.3
13
3.5
48
0.7
1.5
2
40
-
Typ
-
15.5
4.8
50.5
-
Max
35
17
6
53
+0.7
+1.5
+700
+150
Unit
V
kHz
A
A
V
C
5. Ordering information
Table 2.
Ordering information
Package
Name
SSL21151T
SSL21153T
SO7
Description
plastic small package outline body; 7 leads; body width
3.9 mm
Version
SOT1175-1
Type number
SSL2115X
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2012. All rights reserved.
Product data sheet
Rev. 2 — 7 June 2012
2 of 15
NXP Semiconductors
SSL2115X
Low-cost non-dimmable LED driver IC
6. Block diagram
9
&&
(1$%/(
-)(7
'5$,1
66/;
7(03(5$785(
3527(&7,21
26&,/$725 -,77(5
',*,7$/
&21752/
6(1625
6(16(
*1'
6285&(
DDD
'5,9(5
Fig 1.
Block diagram SSL2115X
7. Pinning information
7.1 Pinning
*1'
*1'
*1'
6(16(
DDD
'5$,1
66/;
6285&(
9&&
Fig 2.
Pin configuration
7.2 Pin description
Table 3.
Symbol
GND1
GND2
GND3
SENSE
VCC
SOURCE
DRAIN
Pin description
Pin
1
2
3
4
5
6
7
Description
ground
ground
ground
transformer status sensing
supply voltage
source of the internal power switch
drain of the internal power switch
SSL2115X
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2012. All rights reserved.
Product data sheet
Rev. 2 — 7 June 2012
3 of 15
NXP Semiconductors
SSL2115X
Low-cost non-dimmable LED driver IC
8. Functional description
8.1 Introduction
The SSL2115X is an integrated circuit intended for retrofit small form factor SSL lamps. It
provides a controller with an internal high-voltage switch to drive LEDs. It operates directly
from the rectified mains.
9
'5$,1
9
0
9
L
Q9
RXW
9
L
W
RQ
W
RII
W
VZ
IUHH UXQQLQJ
DDD
V
DRAIN
= voltage on pin DRAIN
t
on
= turn-on time
t
off
= turn-off time
V
M
= peak voltage
V
i
= input voltage
N = transformer winding turns ratio
V
OUT
= output voltage.
Fig 3.
Drain switching wave form
8.2 Current source operation
A flyback inductor is calculated using Equation 1:
I
LED
U
max
L
=
--------------------------------------------------------------------
2
0.85
f
sw
high
0.5
I
pk
Where
(1)
•
is the efficiency of the complete flyback converter
•
f
sw(high)
is the high switching frequency
•
U
max
the maximum combined voltage of the connected LEDs and the voltage drop of
the output rectifier
•
L is the primary inductance of the flyback transformer
•
I
pk
is the peak current through of the flyback transformer
V
ref
high
pk
I
pk
=
--------------------------
-
R
SOURCE
SSL2115X
All information provided in this document is subject to legal disclaimers.
(2)
© NXP B.V. 2012. All rights reserved.
Product data sheet
Rev. 2 — 7 June 2012
4 of 15
NXP Semiconductors
SSL2115X
Low-cost non-dimmable LED driver IC
Where
•
V
ref(high)pk
is the peak high reference voltage
•
R
SOURCE
is the value of the resistor connected to the SOURCE pin
8.3 Leading-Edge Blanking (LEB)
The controller has a fixed LEB of 325 ns to avoid wrong detection of the primary peak
current.
8.4 dV/dt detection
The end of demagnetization is detected when the voltage on the sense pin is <50 mV.
8.5 Turn-off-time (t
off
)
A blanking time is applied at the beginning of t
off
during t
blank
time to observe the
demagnetization.
8.6 Supply concepts VCC and UnderVoltage LockOut (UVLO)
An integrated Junction gate Field-Effect Transistor (JFET), connected to the drain voltage,
provides the start-up current.
The IC starts switching when the voltage on pin VCC exceeds the V
CC(startup)
level. After
start-up, an external supply is required, which an auxiliary winding connection can
provide. When the voltage on pin VCC drops below the V
CC(UVLO)
level, the IC stops
switching and is reset.
Design the voltage of the auxiliary winding to ensure that the VCC supply voltage has a
U
max
value of
29 V
8.7 Peak current detection
The cycle-by-cycle peak drain current limit circuit uses the external source resistor
R
SOURCE
to measure the primary peak current. The circuit is activated after the leading
edge blanking time. The protection circuit limits the source voltage over resistor R
SOURCE
to V
th(det)SOURCE
, thus limiting the primary peak current.
8.8 LED OverTemperature Protection (OTP)
An external temperature dependent resistor can be applied for LED over temperature
protection.
8.9 LED Output Short-circuit Protection (OSP)
When the output short-circuit protection is activated, the IC enters shutdown mode. Only a
power-on reset (switching off the mains voltage) activates normal operation.
8.10 Output LED open-circuit protection
If an open circuit occurs on the LEDs, the output voltage increases at each cycle of the
AC/DC converter. Energy is no longer transferred to the LEDs. The energy accumulated
at the primary side is transferred to the supply of the IC via the auxiliary winding. The IC
SSL2115X
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2012. All rights reserved.
Product data sheet
Rev. 2 — 7 June 2012
5 of 15
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