Datasheet
Table Of Contents
- Figure 1. Typical application circuit
- 1 Pin settings
- 2 Maximum ratings
- 3 Electrical characteristics
- 4 Functional description
- 5 Application notes - buck conversion
- 5.1 Closing the loop
- 5.2 GCO(s) control to output transfer function
- 5.3 Error amplifier compensation network
- 5.4 LED small signal model
- 5.5 Total loop gain
- 5.6 Compensation network design
- 5.7 Example of system design
- 5.8 Dimming operation
- 5.9 Component selection
- 5.10 Layout considerations
- 5.11 Thermal considerations
- 5.12 Short-circuit protection
- 5.13 Application circuit
- 6 Application notes - alternative topologies
- 7 Package mechanical data
- 8 Ordering information
- 9 Revision history
Application notes - buck conversion LED5000
32/51 Doc ID 023951 Rev 1
Equation 49
R1 must be dimensioned to limit the D1 rated power so it is an inexpensive small signal
Zener diode.
The overvoltage limits the output voltage in case of LED disconnection so protecting LEDs
when the string is reconnected with the device enabled. In case the OVP is not
implemented, a large amount of non-controlled current could flow through the LEDs during
the output capacitor discharging phase, thereby damaging the devices.
Table 9. Component list
Reference Part number Description Manufacturer
C1,C2 C3225X7S1H106M 10 μF 50 V (size 1210) TDK
C3,C6 100 nF 50 V (size 0805)
C4 470 pF 50 V (size 00603)
C5 22 pF 50 V (size 0603)
C7 C3216X7R1H105K 1 μF 50 V (size 1206) TDK
C8 Not mounted
D1 STPS3L60U 3 A 60 V ST
D2 BZX384-C4V7
D3 BZX384-C39
L1 MSS7341-473MLD
47 μH
I
SAT
=1.0 A (30% drop)
I
RMS
=1.85 A (40 °C rise)
(size 7.3 x 7.3 x 4.1 mm)
Coilcraft
R
S
ERJ14BSFR27U
0.27 Ω 1%
(size 1206)
Panasonic
R1 10 kΩ 1% (size 0603)
R2 Not mounted
R3 24.9 kΩ 1% (size 0603)
R4 47 kΩ 1% (size 0603)
V
OUT
V
FB
V
ZENER_DIODE
+=
I
ZENER_DIODE
V
FB
R
S
R
1
+
---------------------=