200° C High Voltage Power Supply
General Description
The H25B Series high voltage power supplies are designed to operate at extreme temperatures and in harsh environments especially for the oil well logging industry. The H25B units provide up to 3kV at 100uA of regulated output, with either positive or negative polarity. All models are adjustable over a 3:1 output voltage range by either voltage or resistance programming. Temperature drift is less than 100 ppm/deg C by using advanced internal reference and drift compensation techniques. All models are reverse input and output arc and short circuit protected.
Features
Regulated
Encapsulated and Shielded
Voltage and Resistance programmable
1kV, 2kV and 3kV available
Various input voltages available
Positive or Negative Polarity
H25B Series Application Notes
H25B Series high voltage power supplies are regulated against both line and load changes. Input current as a function of load is shown above, as is output voltage as a function temperature. Setting the output voltage to a fixed value which is lower than the unit’s maximum output can be accomplished by either of two methods. In the resistance programming mode, a resistor is inserted between the Control Pin (Yellow control wire) and the Ground Pin (Green ground wire). For positive output units, a resistance value of zero Ohms yields the maximum output voltage. Figure 1 shows the connections for a positive output power supply. Figure 2 shows the output voltage as a function of control resistor.
HAQ Series
High Temperature High Voltage Power Supply
General Description
The HAQ Series high voltage power supplies are designed specifically for use in high temperature environments. They provide isolated outputs of up 3kV and will operate at 185 degrees C case temperature. The output voltage of the HAQ power supply is directly proportional to the input voltage (0 – 15VDC). The output ripple is typically less than 0.1% at full power load. The two output leads are floating and fully isolated from the inputpower leads by over 1T Ohm (@ 25 deg C) with less than 50 pF of coupling capacitance. This permits either positive or negative polarity operation. The circuitry incorporates the same high efficiency Royer oscillator designed for our H-25B series which has been in production since 1981. All HAQ’s are reverse input voltage and short circuit protected.
Features
Output proportional to Input
Encapsulated
500 VDC to 3,000 VDC available
1.5 Watt power
Metal case for low ripple: 0.1% Vpp
HAQ Series Application Notes
The HAQ Series high voltage power supplies are driven by an input voltage of 1 to 15 VDC. The input current and output voltage as a function of input is shown in the above graphs. There are NO internal connections between the input and output pins. As can be seen from the above, the output voltage is approximately linear with respect to input except near the lower input voltage region. Here, the output drops off rapidly as the input voltage approaches zero with the absolute minimum input voltage needed for reliable starting being 2 VDC. As shown in Figure 1 below, the simple connection of a HAQ unit to a DC source of voltage will provide a high voltage stepped-up output. The input AC bypass capacitor C1 is optional and is utilized to prevent switching spikes from riding back on the input power lines. Values of 0.1 uF to 10 uF are commonly used.
The output voltage of the HAQ unit may be regulated by incorporating a simple op-amp circuit and linear control device such as an NPN transistor. Here, the output voltage is sensed and compared against an external reference control voltage. For single supply operation, the circuit of Figure 2 may be used for positive output regulation. A high voltage divider is made up of R5 and R6 to divide down the output to a value comparable with the control voltage. The resistor R5 is value is determined by power considerations. A good rule of thumb is to be 10% of the full output load. Too high a value may lead to output drift problems due to operational amplifier input bias current drift. The resistor R5 must be rated for the voltage that it is to step down. Simple high value carbon film resistors are usually avoided because their maximum voltage is limited to 300 VDC. Precision metal film resistors are more stable but also have limiting maximum voltages. It is possible to series several metal film resistors to build up the voltage rating of R5. Capacitor C4 likewise must be rated for the proper voltage. It serves to lower output ripple provide a feed-forward pole in the feedback loop for stability. Capacitor C5, the ground mirror capacitor serves as a lower end of the AC divider formed with C4 and prevents excessive voltage from being fed to the operational amplifier in the case of a shorted output.
HTC Series
200° C High Voltage Power Supply
General Description
The HTC Series high voltage power supplies are designed to operate at extreme temperatures and in harsh environments especially for the oil well logging industry. The HTC units provide up to 3kV at 100uA of regulated output, with either positive or negative polarity. All models are adjustable over a 3:1 output voltage range by either voltage or resistance programming. Temperature drift is less than 100 ppm/deg C by using advanced internal reference and drift compensation techniques. All models are reverse input and output arc and short circuit protected.
Features
Regulated
Encapsulated and Shielded
Voltage and Resistance programmable
1kV, 2kV and 3kV available
Various input voltages available
Positive or Negative Polarity
Low Temperature Drift (+/-10VDC) Option available
HTC Series Application Notes
HTC Series high voltage power supplies are regulated against both line and load changes. Input current as a function of load is shown above, as is output voltage as a function temperature. Setting the output voltage to a fixed value which is lower than the unit’s maximum output can be accomplished by either of two methods. In the resistance programming mode, a resistor is inserted between the Control Pin (Yellow control wire) and the Ground Pin (Green ground wire). For positive output units, a resistance value of zero Ohms yields the maximum output voltage. Figure 1 shows the connections for a positive output power supply. Figure 2 shows the output voltage as a function of control resistor.
HTR/HTDR Series
200° C High Voltage Power Supply
General Description
The HTR/HTDR Series high voltage power supplies are designed to operate at extreme temperatures and in harsh environments especially for the oil well logging industry. The HTR/HTDR units provide up to 3kV at 100 uA of regulated output, with either positive or negative polarity. All models are adjustable over a 3:1 output voltage range by either voltage or resistance programming. Temperature drift is less than 100 ppm/deg C by using advanced internal reference and drift compensation techniques. All models are reverse input and output arc and short circuit protected.
Features
Regulated
Encapsulated and Shielded
Voltage and Resistance programmable
1kV, 2kV and 3kV available
Various input voltages available
Positive or Negative Polarity
Low Temperature Drift (+/-10VDC) Option available
HTR/HTDR Series Application Notes
HTR/HTDR Series high voltage power supplies are regulated against both line and load changes. Input current as a function of load is shown above, as is output voltage as a function temperature. Setting the output voltage to a fixed value which is lower than the unit’s maximum output can be accomplished by either of two methods. In the resistance programming mode, a resistor is inserted between the Control Pin and the Ground Pin. For positive output units, a resistance value of zero Ohms yields the maximum output voltage. Figure 1 shows the connections for a positive output power supply. Figure 2 shows the output voltage as a function of control resistor.