SSL1623PH_1

© NXP B.V. 2008. All rights reserved.

Product data sheet

Rev. 01 — 15 September 2008

7 of 15

NXP Semiconductors

SSL1623PH

8.5 Demagnetization

The system operates in discontinuous conduction mode all the time. As long as the

secondary stroke has not ended, the oscillator will not start a new primary stroke. During

suppression may be necessary in applications where the transformer has a large leakage

inductance and at low output voltages.

8.6 Protections

8.6.1 Overcurrent protection

(see Figure 5) to measure the current. The circuit is activated after the leading edge

limits the primary peak current.

8.6.2 Short winding protection

The short winding protection circuit is also activated after the leading edge blanking time.

stops switching. Only a power-on reset will restart normal operation. The short winding

protection also protects in case of a secondary diode short circuit.

8.6.3 Overtemperature protection

An accurate temperature protection is provided in the SSL1623PH. When the junction

temperature exceeds the thermal shutdown temperature, the IC stops switching. During

thermal protection the IC current is lowered to the start-up current. The IC continues

normal operation as soon as the overtemperature situation has disappeared.

Reflected voltage at N

× V

Fig 4.

Typical phase of drain ringing at switch-on

f (kHz)

0

800

600

200

400

001aaa311

0

−20

20

40

phase

(

°)

−40