ssl2101 NXP Semiconductors, ssl2101 Datasheet - Page 8

• Manufacturer Part Number: ssl2101
• Description: Smps Ic For Dimmable Led Lighting
• Manufacturer: NXP Semiconductors

NXP Semiconductors
SSL2101_1
Preliminary data sheet
As soon as the oscillator voltage is high again and the secondary stroke has ended, the
circuit waits for a low drain voltage before starting a new primary stroke.
Figure 6
secondary stroke and the RC voltage.
The primary stroke starts some time before the actual valley at low ringing frequencies,
and some time after the actual valley at high ringing frequencies.
Figure 7
80 V. This voltage is the output voltage transferred to the primary side of the transformer
with the factor N (determined by the turns ratio of the transformer). It shows that the
system switches exactly at minimum drain voltage for ringing frequencies of 480 kHz, thus
reducing the switch-on losses to a minimum. At 200 kHz, the next primary stroke is
started at 33 before the valley. The switch-on losses are still reduced significantly.
Fig 6. Signals for valley switching, flyback configuration
A: Start of new cycle with valley switching.
B: Start of new cycle in a classical PWM system.
shows the drain voltage together with the valley signal, the signal indicating the
shows a typical curve for a reflected output voltage N at an output voltage of
secondary
oscillator
stroke
valley
drain
RC
Rev. 01 — 19 January 2009
primary
stroke
regulation level
secondary
stroke
SMPS IC for dimmable LED lighting
secondary
ringing
B
014aaa572
A
SSL2101
© NXP B.V. 2009. All rights reserved.
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