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HD1xxxx Series
High Voltage Transistors for Horizontal Deflection in Ultrahigh Resolution CRT Displays
 
HD1xxxx Product Selector

The boom in multimedia activities has brought with it the demand for larger and “real-flat” screen sizes for high quality images. As a result, more and more stringent performance is requested from the switches used in the horizontal deflection stage. A new product range specifically developed to respond to the needs of this high-end market has just been introduced.
  
High Voltage Transistors for Horizontal Deflection in Ultrahigh Resolution CRT Displays
The HD1xxxx series has been designed by adopting a new advanced silicon technology known as Enhanced High Voltage Structure (EHVS1).
The new EHVS1 technology represents a step forward in the optimization of the trade-off between the on and switching losses. In fact, thanks to the higher switching frequency and lower on-losses offered by the new products it is now possible to focus on high-end digital TVs, rear-projection TVs, as well as highly-professional monitor displays such as those required for medical applications, or high-resolution CRT displays, working at high horizontal frequencies (over 100kHz).

EHVS1 Technology

The EHVS1 is a planar technology realized by a float-zone collector on a diffused substrate with a re-designed high voltage edge structure. The silicon efficiency has been significantly improved thanks to the reduction of the capacitance in the base-collector junction by adopting a special deep-base process. As a result, devices belonging to the HD1 series are able to sustain very high breakdown voltages and at the same time exhibit both high current capability and high switching speeds.


Main Features of HD1xxxx Series

Wide range of optimum drive conditions;
Less sensitivity to the variation of the operating temperature;
Improved R.B.S.O.A for safer switching performance;
Reduced saturation voltage at high current;
High performance 1700V products.

Reduced Power Losses

Horizontal deflection requires an application specific characterization to describe the input requirements needed to minimize the power losses. The following graph shows the power losses versus the variation of the base current (IBon) at a fixed output current of 12A and a switching frequency of 32kHz; these conditions represent the worst case conditions in wide screen 100Hz TVs. A comparison with the most advanced device from competition shows the better performance of HD1750FX (about 1W less).

High Voltage Transistors for Horizontal Deflection in Ultrahigh Resolution CRT Displays
Power losses curves comparison

A Cooler More Reliable System

The HD1750FX requires a lower base current thus reducing the power dissipation in the passive components used in the deflection block, this makes the system a lot cooler and more reliable. It is worth noticing also that the HD1750FX can operate with a larger IBon range to ensure the best driving conditions, minimizing as a result the normal hfe variation with temperature. The figure below shows the switching waveforms during an application test performed on a commercial wide real-flat screen TV working at a switching frequency of 32kHz.

High Voltage Transistors for Horizontal Deflection in Ultrahigh Resolution CRT Displays
Application oriented switching waveforms


The HD1750FX shows satisfactory performance also at 100kHz confirming its suitability also in high-resolution 19” monitors as shown in the losses behaviour graph. This curve is for the ISOWATT218FX package while even better performance can be achieved with the same device housed in TO-264.

High Voltage Transistors for Horizontal Deflection in Ultrahigh Resolution CRT Displays
HD1750FX power losses behaviour

Part Numbering Description

Since the new series has been developed specifically for horizontal deflection, the part numbers follow the scheme below.

High Voltage Transistors for Horizontal Deflection in Ultrahigh Resolution CRT Displays


R.B.S.O.A

Beside the features that characterize this technology the HDxxxx series also exhibits a larger RBSOA, offering additional security during turn-off, where the device could be overstressed by the high fly-back voltage and the high current which are both present in anomalous conditions.
High Voltage Transistors for Horizontal Deflection in Ultrahigh Resolution CRT Displays
Safe operationg area of HD1520FX
 

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