SLUAAL2 Application note

Table 1-2 160W LED Driver Specifications

PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNITS
INPUT CHARACTERISTICS
DC voltage range (V_in)		365	390	410	V
LED CHARACTERISTICS[10]
Forward Voltage at I_F=1 A		2.8	3.2	3.8	V
Rated Forward Current (I_F)			1		A
Forward Voltage at I_F=100 mA			2.8		V
OUTPUT CHARACTERISTICS [11]
LED Array Voltage (V_out) (Array consists of three branches and each branch has 14 LEDs )		39.2	44.8	53.2	V
LED Array Current		0.3 (100mA per branch)		3	A
Output Power at LED array current = 3 A		117.6	134.4 (P_{out_typ})	159.6 (P_{out_Max})	W
Output Power at LED array current = 0.3 A (P_{out_Min})			11.76		W
Output Voltage Ripple				300	mVpp
Output Voltage at No Load				57	V
Resonant frequency f_res			100		kHz
Peak efficiency	At Peak output Power		92%

The LLC tank parameters and the turns ratio are chosen based on the $V_{i n_t y p} = 390 V,$ $V_{o u t_t y p} = 44.8 V,$ $P_{o u t_t y p} = 134.4 W,$ $f_{r e s} = 100 k H z$ . This is shown in Figure 1-31 [12].
It is important to make sure that the maximum and minimum gain requirements are met once the tank parameters have been chosen.
$Maximum Gain and Minimum frequency (G_{max} = \frac{V_{out_Max}}{V_{in_Min}}) {requirement occurs at P}_{out_Max}$ $Where as Minimum Gain and Maximum frequency (G_{min} = \frac{V_{out_Min}}{V_{in_Max}}) {requirement occurs at P}_{out_Min}$ . These are shown in Figure 1-32 and Figure 1-33.
To protect the converter against the over voltage during no load, output voltage is regulated at 57 V.

Figure 1-28 LLC Design for Typical Output Voltage of the LED Driver and at Typical Output Power

Figure 1-29 LLC Maximum Gain Verification at Maximum Output Power

Figure 1-30 LLC Minimum Gain Verification at Minimum Output Power