SSL4101T View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'SSL4101T' PDF : 29 Pages View PDF
NXP Semiconductors
SSL4101T
GreenChip III+ SMPS control IC
Vsense(fb)max
(V)
0.52 V
FBSENSE peak voltage
0.13 V
PFC off
PFC on
flyback
frequency
reduction
flyback
cycle skip
mode
flyback
discontinuous
or QR
1.4 V 1.5 V 2.0 V VFBCTRL (V)
014aaa160
Fig 9. Peak current control of flyback part
The driver output is latched in the logic, preventing multiple switch-on.
7.3.4 Demagnetization (FBAUX pin)
The system is always in quasi-resonant or discontinuous conduction mode. The internal
oscillator does not start a new primary stroke until the previous secondary stroke has
ended.
Demagnetization features a cycle-by-cycle output short circuit protection by immediately
lowering the frequency (longer off-time), thereby reducing the power level.
Demagnetization recognition is suppressed during the first tsup(xfmr_ring) time (2 μs typical).
This suppression may be necessary at low output voltages and at start-up and in
applications where the transformer has a large leakage inductance.
If pin FBAUX is open circuit or not connected, a fault condition is assumed and the
converter stops operating immediately. Operation restarts as soon as the fault condition is
removed.
7.3.5 Flyback control/time-out (FBCTRL pin)
The pin FBCTRL is connected to an internal voltage source of 3.5 V via an internal
resistor (typical resistance is 3 kΩ). As soon as the voltage on this pin is above
2.5 V (typical), this connection is disabled. Above 2.5 V the pin is biased with a small
current. When the voltage on this pin rises above 4.5 V (typical), a fault is assumed and
switching is inhibited. In the SSL4101T, a restart will then be made.
When a small capacitor is connected to this pin, a time-out function can be created to
protect against an open control loop situation. (see Figure 10 and Figure 11) The time-out
function can be disabled by connecting a resistor (100 kΩ) to ground on the FBCTRL pin.
If the pin is shorted to ground, switching of the flyback controller is inhibited.
In normal operating conditions, when the converter is regulating the output voltage, the
voltage on the FBCTRL pin is between 1.4 V and 2.0 V (typical values) from minimum to
maximum output power.
SSL4101T
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 21 April 2011
© NXP B.V. 2011. All rights reserved.
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