User's Manual Part 1

CL1TC-4 400W DVB-H Transmitter Product Description

Product Manual, Rev. 1 20

2.3.5.1 HPA Enhanced Features and Design Concepts

he HPA utilizes several innovative features designed to enhance its performance and

reliability of the amplifier.

• Enhanced Heat Sink Design

• Thermally Enhanced Power Transistors

• Variable speed (temperature controlled) DC fans

The HPA employs a heat sink design that permits more equal heat distribution across the

heat sink, thus reducing the maximum operating temperature. Distribution of the main

heat source elements within the HPA is optimized in order to utilize the maximum thermal

efficiency from the heat sink, also resulting in lower operating temperatures.

The HPA design incorporates the latest generation high power LDMOS transistors which

employ a thermally enhanced package. The significant reduction in thermal resistance will

allow these new generation power devices to operate with a lower junction temperature

thus improving overall amplifier reliability.

The variable speed fans allow the fan speed to be increased or decreased as the HPA

temperature increases or decreases. This improves overall efficiency of the HPA and the

lifetime of the fans.

2.3.5.2

HPA Controller

The HPA

embedded controller monitors all operating parameters and provides amplifier

protection and control. It communicates with the main system controller via the RS485

interface and reports the following parameters and statuses:

• HPA input power level

• HPA forward power level

• HPA reflected power level

• HPA power supply DC voltage levels

• HPA pre-driver, driver and power module current consumption

• HPA temperature

• HPA fan speed

• HPA RF power inhibit

• HPA input overdrive alarm

• HPA output overdrive alarm

• HPA output reflected power (VSWR) alarm

• HPA failure alarm

• Over-temperature fault

• Pre-drive and driver device (current) fault

• Power module current misbalance fault (results is output power limitation)

• Power module device (current) fault

• Power Supply DC Fault

• Fan stalled alarm