STEVAL-ILL027V1 STMicroelectronics, STEVAL-ILL027V1 Datasheet - Page 9

• Manufacturer Part Number: STEVAL-ILL027V1
• Description: BOARD EVAL LED DRIVER FOR L6562A
• Manufacturer: STMicroelectronics

Specifications of STEVAL-ILL027V1

• Design Resources: STEVAL-ILL027V1 Schematics STEVAL-ILL027V1 BOM STEVAL-ILL027V1 Gerber Files
• Current - Output / Channel: 260mA
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 70V
• Features: Short-Circuit Protection
• Voltage - Input: 120VAC
• Utilized Ic / Part: L6562A
• Product: Display Modules
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Other names: 497-10170

AN3111
From
Equation 12
A 1 Ω current sensing resistor can be used in the application. To better handle the high
current, two SMT 2 Ω resistors are implemented.
Operating principles:
The operation of the converter can be described as follows:
●
●
●
●
●
●
●
Figure 4.
The MOSFET Q1 operates zero voltage turn-on when the instant input voltage is lower than
the output voltage. It is turned on at reduced voltage when the input voltage is higher than
the output voltage. Therefore, it is a partial soft-switched converter.
The period of t0 to t3 is near the line voltage zero crossing. The period of t4 to t7 is
around the peak line voltage.
[t0,t1], Q1 is turned on at time t0. The inductor current reaches its peak at t1. Near the
line voltage zero crossing, the peak amplitude is lower than the constant value Ipk.
[t1,t2] Q1 is turned off at t1. The inductor current decreases to zero at t2.
[t2,t3] the drain voltage of Q1 starts to fall at t2, and reaches zero at t3. The ZCD pin of
the controller detects the ZCD signal low and turns on Q1 again at t3. Q1 is turned on
at zero voltage.
[t4,t5], Q1 is turned on at time t4. The inductor current reaches its peak at t4. The peak
amplitude is the constant value Ipk.
[t5,t6] Q1 is turned off at t5. The inductor current decreases to zero at t6.
[t6,t7] the drain voltage of Q1 starts to fall at t6, and reaches its minimum value at t7,
but it does not reach zero. The ZCD pin of the controller detects the ZCD signal low and
turns on Q1 again at t7. Q1 is turned on at reduced voltage.
Equation 6
Illustration of key waveforms of the converter
, we have:
Doc ID 16815 Rev 2
L
=
fsw
max*
L
1
=
Ipk
200 μH
(
Vpk
Vout
+
*
Vout
Vpk
)
Circuit design
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