Si9113DB

Features:

ISDN-NT Input Voltage Range 28 V to 99 V
Non-Polar Input
3.3-V/120-mA, 40-V/12-mA Outputs With Up To 80% Efficiency
Up to 68% Efficiency at 80-mW Load
40 V Isolated By 3 kV From Input And 3.3-V Output Si9113D1
3.3 V, 40 V Isolated By 1.5 kV From Input/Each Other Si9113D2
Current Mode Control, 0.6-V Fast Over-Current Protection
Max 50% Duty Cycle Operation
1.3-MHz Error Amp
Soft-Start
<10-A Supply Current for +V_IN<18  V
Programmed Start/Stop
Internal Start-Up Circuit
Power_Good Output




Description

As discussed in application note, AN728, the Si9113 power supply controller is an ideal choice for ISDN terminal equipment, where high efficiency at a low power level is one of most important criteria. Therefore, Vishay Siliconix has developed versions of a dual output flyback application demonstration boards, the Si9113D1 and the Si9113D2, which use different regulation schemes. These readily available demo boards are configured to deliver approximately 800 mW at 3.3-V, and40-V.  These outputs and can be easily modified for other output voltages at approximately same power level.The flyback converters are designed to operate from a wide input voltage range of 28 V to 99 V and are polarity protected by a diode bridge. The Si9113D1 and Si9113D2, both operate at 20-kHz switching frequency to achieve the best possible efficiency. The transformer is selected to be slightly larger in this application so that the same area product would be good enough for an even lower window utilization factor (w.u.f.)
transformer in order to meet the stringent requirements of clearance and creepage distances.

The Si9113D1 senses and tightly regulates the main outputV_OUT1(3.3 V), which has the common ground as input and the secondary output V_OUT2
(40 V) is regulated to within ±10% at 10% to100% load range, including the set point accuracy.Correspondingly. the transformer must be specified with tight tolerance to achieve the given set point accuracy. The 40-V output is isolated from both the input and 3.3-V output by minimum 3 kV_rms
 isolation.

The Si9113D2 uses the auxiliary output (V_CCbootstrap winding) for sensing. Both V_OUT1(3.3 V) and V_OUT2(40 V) follow the auxiliary output, residing on one core and sharing the same flux. Both the outputs are isolated from the input as well as from each other by 1.5 kV and moderately regulated to±5%.

Each demonstration board uses all surface mount components except the high voltage electrolyte capacitor and are fully assembled and tested for quick evaluation. Test points are provided for the power_good signal and the closed loop response measurement.

Included in this document are the Bill-Of-Materials,Schematics, PCB Layout of the Demo Boards and actual waveforms/graphs.