LNB power supply electronic circuit using ISL9492
A very simple LNB power supply electronic circuit can be designed using the ISL9492 a highly integrated voltage regulator and interface IC specifically designed for supplying power and control signals from advanced satellite set-top box (STB) modules to the low noise blocks (LNB) of a single antenna port.
This circuit is very simple and require few external electronic parts ( as you can see in circuit diagram ) .
It also supports DiSEqC tone generation and modulation with diagnostic status read-back. Controlling the ISL9492 is simple via the I2C bus by writing 8 bit words onto the System Registers (SR).
The ISL9492 device design makes the total LNB supply design simple, efficient and compact with low external component providing high efficiency , more than 92% .
The LNB output voltage can be controlled in two ways; by full control from I2C using the VTOP and VBOT bits or by setting the I2C to the lower range and switching to higher range with the select VTOP pin.
The External modulation input EXTM accepts a modulated DISEqC command and transfers it symmetrically to the output. The fault signal serves as an interrupt for the processor when any condition turns OFF the LNB controller (over-temperature, overcurrent, disable).