SSL2103
SMPS controller IC for dimmable LED lighting
Rev. 2 — 25 November 2010
Product data sheet
1. General description
SSL2103 is a Switched Mode Power Supply (SMPS) controller IC designed for LED
lighting applications. It is an extension of the NXP SSL2101/SSL2102 product platform,
allowing easy design of derivative applications.
When used in combination with a phase cut dimmer connected directly to a rectified
mains, it provides dimmability to the application.
In dimmer applications, integrated dedicated circuitry optimizes the dimming curve.
•
SSL2101: fully integrated LED driver for lamps up to 10 W
•
SSL2102: fully integrated LED driver for lamps up to 25 W
•
SSL2103: gives the application designer flexibility permitting the:
–
control of an external power switch to allow the IC to provide any power
–
control of external bleeder transistors to provide extended dimmer interoperability
The device includes a circuit that allows start-up directly from the rectified mains voltage.
2. Features and benefits
Easy migration to existing lighting control infrastructures, TRIAC and transistor
dimmers
Compatible with most dimming solutions
Optimized efficiency with valley switching managed by built-in circuitry
Built-in demagnetization detection
Built-in OverTemperature Protection (OTP)
Short-Winding Protection (SWP) and OverCurrent Protection (OCP)
Internal V
CC
generation allowing start-up from rectified mains voltage
Natural dimming curve by logarithmic correction, optimized for human eye response,
down to 1 %
3. Applications
The SSL2103 is suitable for various power requirements including:
Retro-fit lamps
LED modules such as LED spots and down-lights
LED strings suitable for retail displays etc.
NXP Semiconductors
SSL2103
SMPS controller IC for dimmable LED lighting
4. Quick reference data
Table 1.
Symbol
V
CC
f
osc
I
DRAIN
min
max
T
amb
[1]
Quick reference data
Parameter
supply voltage
oscillator frequency
current on pin DRAIN
minimum duty factor
maximum duty cycle
ambient temperature
PWMLIMIT= 3 V
V
DRAIN
> 60 V; with auxiliary supply
Conditions
V
DRAIN
60 V
[1]
Min
12
10
-
-
-
40
Typ
20
100
30
0
75
-
Max
28
130
125
-
-
+100
Unit
V
kHz
A
C
V
CC
= 20 V minimum to meet all characteristics.
5. Ordering information
Table 2.
Ordering information
Package
Name
SSL2103T
SO14
Description
plastic small outline package; 14 leads; body width 3.9 mm
Version
SOT108-1
Type number
SSL2103
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2010. All rights reserved.
Product data sheet
Rev. 2 — 25 November 2010
2 of 21
NXP Semiconductors
SSL2103
SMPS controller IC for dimmable LED lighting
6. Block diagram
SB_DRV
ISENSE
9
1
BLEEDER
V
CC
3
SUPPLY
13
DRAIN
WB_DRV
2
HVDET
14
VALLEY
10
GND
4
LOGIC
100 mV
AUX
12
Stop
RC
7
OSCILLATOR
Low freq
THERMAL
SHUTDOWN
PROTECTION
LOGIC
BRIGHTNESS
RC2
5
6
FREQUENCY
REDUCTION
CIRCUIT
POWER - UP
RESET
0.5 V
PWR_DRV
Blank
11
SOURCE
1.5 V
PWMLIMIT
8
PWM
LIMIT
CIRCUIT
Overcurrent
Short-winding protection
SSL2103
001aam651
Fig 1.
Block diagram
SSL2103
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2010. All rights reserved.
Product data sheet
Rev. 2 — 25 November 2010
3 of 21
NXP Semiconductors
SSL2103
SMPS controller IC for dimmable LED lighting
7. Pinning information
7.1 Pinning
SB_DRV
WB_DRV
V
CC
GND
BRIGHTNESS
RC2
RC
1
2
3
4
5
6
7
001aam652
14 HVDET
13 DRAIN
12 PWR_DRV
SSL2103
11 SOURCE
10 AUX
9
8
ISENSE
PWMLIMIT
Fig 2.
Pin configuration SO14
7.2 Pin description
Table 3.
Symbol
SB_DRV
WB_DRV
V
CC
GND
BRIGHTNESS
RC2
RC
PWMLIMIT
ISENSE
AUX
SOURCE
PWR_DRV
DRAIN
HVDET
Pin description
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Description
strong bleeder switch drive
weak bleeder switch drive
supply voltage
ground
brightness input
setting for frequency reduction
frequency setting
PWM limit input
current sense input for WBLEED
input for voltage from auxiliary winding for timing (demagnetization)
current sense input of external power switch
power switch drive
drain of external power switch; input for start-up current and valley sensing
input for high voltage sensing
SSL2103
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2010. All rights reserved.
Product data sheet
Rev. 2 — 25 November 2010
4 of 21
NXP Semiconductors
SSL2103
SMPS controller IC for dimmable LED lighting
8. Functional description
The SSL2103 is a LED driver IC that operates directly from the rectified mains. The
SSL2103 uses on-time mode control and frequency control to control the LED brightness.
The BRIGHTNESS and PWMLIMIT input of the IC can be used to control the LED light
output in combination with an external dimmer. The PWMLIMIT input can also be used for
Thermal Lumen Management (TLM) and for precision LED current control.
8.1 Start-up and Under Voltage Lock Out (UVLO)
Initially, the IC is self-supplying from the rectified mains voltage. The IC starts switching as
soon as the voltage on pin V
CC
passes the V
CC(startup)
level. The supply can be taken over
by the auxiliary winding of the transformer as soon as V
CC
is high enough and the supply
from the line is stopped for high efficiency operation. Alternatively the IC can be supplied
via a bleeder resistor connected to a high voltage.
Remark:
The maximum V
CC
voltage rating of the IC must be considered.
8.2 Oscillator
An oscillator inside the IC provides the timing for the switching converter logic.
The frequency of the oscillator is set by the external resistors and the capacitor on pin RC
and pin RC2. The external capacitor is charged rapidly to the V
RC(max)
level and, starting
from a new primary stroke, discharges to the V
RC(min)
level. Because the discharge is
exponential, the relative sensitivity of the duty factor to the regulation voltage at low duty
factor, is almost equal to the sensitivity at high duty factors. This results in a more constant
gain over the duty factor range, compared to Pulse Width Modulated (PWM) systems with
a linear sawtooth oscillator. Stable operation at low duty factors is easily achieved. The
frequency of the converter when V
BRIGHTNESS
is high can be calculated using
Equation 1:
1
1
-
RC
=
------
-------
–
t
ch arg e
-
3.5
f
osc
(1)
R equals the parallel resistance of both oscillator resistors. C is the capacitor connected at
the RC pin (pin 7).
The BRIGHTNESS input controls the frequency reduction mode.
Figure 3
shows that the
oscillator switches over from an RC curve with R1/R2, to R1 only. A low BRIGHTNESS
voltage will reduce the switching frequency.
SSL2103
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2010. All rights reserved.
Product data sheet
Rev. 2 — 25 November 2010
5 of 21