02001346 Rev 1
HPP-1000/6000 User Manual
Page 9 of 19
6.
LDD/HPP integration and theory of operation
The HPP was designed to work with Lumina Power’s LDD power supplies with the HP
option, which is the output voltage programmable feature.
The complete system includes:
1
LDD-pp-xx-yy-HP where pp is max power, xx is max current, yy is max output
voltage and HP designates output voltage program feature.
2
HPP-pp-xx-yy-zz. pp is maximum average power, xx is maximum output current,
yy is maximum load voltage, zz is maximum pulse width up to CW.
3
HPP Isolator PCB. Due to possible ground loops at high pulsing current and
frequency, the isolator PCB will be inserted between the HPP and the customers’
control system to break the ground loop.
Isolator PCB theory of operation:
The Isolator has 2 electrically isolated sections: one is connected to the HPP and another
is connected to the customer’s control system.
The HPP supplies 15V to operate the isolator pc board. The customer’s control system
must supply 15V to run the section that is connected to the customer’s controller per HPP
pin out assignment.
The Isolator carries all control signals through linear optocouplers for analog signals and
logic optocouplers for logic signals. The pin outs of the isolator PCB is 1-to-1 as an
extension of the control cable with a male connector for the customer’s controller and a
female connector for the HPP.
HPP theory of operation.
The HPP is a High Power Pulser. It is a linear current regulator with fast rise and fall
time. The input voltage of the HPP must be higher than its output voltage. The ratio of
Vout/Vin is roughly its efficiency.
The HPP is the most efficient pulser on the market given the rise time and fall time better
than 15µs. In pulse mode, it communicates with the LDD power supply to adjust the
LDD output voltage which is the HPP input voltage to match the load voltage. The
average input voltage for a given load varies due to pulse current, pulse width but is
regulated such that at the end of the pulse, there will be about 1V across the “linear
regulator”. The average input voltage is higher than the load voltage because the voltage
on the internal capacitors will have some droop during the pulse.
The HPP utilizes a proprietary scheme to have fast rise time even though the input
voltage is a few volts higher than the output voltage and this gives the HPP the highest
efficiency for a linear regulator and the inductance of the output cable seems to have
disappeared.
This feature also allows the voltage tracking when the laser diodes get hot and reduce
their forward voltage drop, V
f
.
