Texas Instruments TPS92310 Evaluation Module TPS92310-23FB/NOPB TPS92310-23FB/NOPB TPS92310-23FB/NOPB Datenbogen
Produktcode
TPS92310-23FB/NOPB
U1
GATE
ISNS
MODE2
PGND
MODE1
1
COMP
ZCD
AGND
AGND
DLY
VCC
2
3
4
5
5
10
9
9
8
7
6
7
6
1A 100V
T
1
2200 pF
Q
1
R
ISNS
66 k
Q
11 k
Q
1A 600V
20
Q
CDSU4148
6.34 k
Q
BAV20
35V
0.5A
600V
22
Q
47 nF
0.1
P
F
3.3 mH
VR1
0.5A
250V
100 k
Q
1.52
Q
15 pF
TPS92310
LED+
LED-
6
±
7
LED
90-135
VAC
L
P
L
S
L
AUX
10
P
F
100 k
Q
470
P
F
10
P
F
2.2
P
F
0.1
P
F
D
1
R
1a
R
1b
L
1
C
IN
C
1
*Z
1
R
4
D
2
R
2
R
3
C
ZCD
C
VCC
D
ZCD
C
COMP
R
DLY
C
AC
C
OUTa
C
OUTb
D
3
R
AC
N
P
: N
S
: N
AUX
= 3.8
: 1
: 1
*Optional
STD3NK80Z
SNVS792 – FEBRUARY 2012
(16)
In here, snubber clamp voltage, V
SN
= 250V is recommended.
Output Capacitor
The capacitance of the output capacitor is determined by the equivalent series resistance (ESR) of the LED,
R
R
LED
and the ripple current allowed for the application. The equation in below can be used to calculate the
required capacitance.
(17)
Assume the ESR of the LED stack contains 7 LEDs and is 2.6
Ω
, AC line frequency f
AC
is 60Hz.
In this example, LED current I
LED
is 350mA and output ripple current is 30% of I
LED
:
(18)
Then, C
OUT
= 480
μ
F.
In here, a 470
μ
F output capacitor with 10
μ
F ceramic capacitor in parallel is suggested.
PCB Layout Considerations
The performance of any switching power supplies depend as much upon the layout of the PCB as the
component selection. Good layout practices are important when constructing the PCB. The layout must be as
neat and compact as possible, and all external components must be as close as possible to their associated
pins. High current return paths and signal return paths must be separated and connect together at single ground
point. All high current connections must be as short and direct as possible with thick traces. The gate pin of the
switching MOSFET should be connected close to the GATE pin with short and thick trace to reduce potential
electro-magnetic interference. For off-line applications, one more consideration is the safety requirements. The
clearance and creepage to high voltage traces must be complied to all applicable safety regulations.
component selection. Good layout practices are important when constructing the PCB. The layout must be as
neat and compact as possible, and all external components must be as close as possible to their associated
pins. High current return paths and signal return paths must be separated and connect together at single ground
point. All high current connections must be as short and direct as possible with thick traces. The gate pin of the
switching MOSFET should be connected close to the GATE pin with short and thick trace to reduce potential
electro-magnetic interference. For off-line applications, one more consideration is the safety requirements. The
clearance and creepage to high voltage traces must be complied to all applicable safety regulations.
Figure 25. Isolated topology schematic
Copyright © 2012, Texas Instruments Incorporated
17
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