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H2W Technologies LPAM-1 User Manual

Manual is about: Linear Power Amplifier Module

Summary of LPAM-1

  • Page 1

    Linear power amplifier module user's guide version 2.0

  • Page 2

    Table of contents table of contents technical specifications.........................................................................................7 absolute maximum ratings.....................................................................7 amplifier specifications.................................

  • Page 3

    Table of contents connecting multiple units.....................................................................41 appendix a............................................................................................................45 dimensions.........................................................

  • Page 4

    List of figures table of figures figure 1. Layout of the amplifier board and the various features................................9 figure 2. Amplifier mode selection jumper....................................................................13 figure 3. Power supply monitor jumper location..............

  • Page 5

    List of tables list of tables table 1. User connection header signal names and pinout........................................12 table 2. Details of the various configuration options...................................................17 table 3. Recommend values for the forward gain in current mode......

  • Page 6

    Linear power amplifier module lpam-1 key features • linear - designed for low noise operation • high output current: 7a continuous output 9a peak output • wide power supply range: 27 volts to 60 volts • wide bandwidth: >10khz in current mode >10khz in voltage mode • dual mode operation: voltage mode...

  • Page 8: Technical Specifications

    Technical specifications technical specifications absolute maximum ratings parameter value units supply voltage 60 v output current continuous peak 7 9 a a input (command) voltage supply voltage = 27 v supply voltage = 48 v +/- 10 +/- 20 v v operating temperature (ambient temperature, natural convec...

  • Page 9

    Amplifier specifications parameter min max typical units disable input signal high ttl level, 5v low ttl level, 0v 1 1 ma ma amplifier fault output ttl compatible, with 200 ohm resistor inline (current limited to 25 ma) 0 5 v current sense output (buffered) 1 ma current limit output reference voltag...

  • Page 10: Amplifier Board Layout

    Amplifier board layout amplifier board layout this section of the manual describes the general layout of the board, and the location of key features. Refer to this diagram when making connections and when locating functions on the board. Power amplifier module user's guide 9 figure 1. Layout of the ...

  • Page 12: Pinouts

    Pinouts pinouts this section explains the various connections that can be made to the amplifier module. Note that all connections should be securely made with the proper connectors. Improper connections may result in poor performance, or may possibly damage the amplifier and other connected equipmen...

  • Page 13

    User connection header pin number signal comments 1 +5v available for signal conditioning circuitry, 10ma max. 2 gnd ground connection. 3 -5v available for signal conditioning circuitry, 10ma max. 4 ref - command signal negative or ground reference. 5 ref + command signal positive or signal. 6 curre...

  • Page 14: Amplifier Mode Select

    Amplifier mode select amplifier mode select voltage / current selection header the amplifier is designed to function either as a voltage amplifier or a current amplifier. Selection of what mode the amplifier operates in is by way of a jumper. Placing jumper j1 in the 1-2 position selects voltage mod...

  • Page 15: Power Supply Monitor Enable

    Amplifier mode select amplifier uses a built in current feedback loop to continuously change the voltage applied to the load so the commanded current is always applied to the load. The maximum continuous current available is 7a. Consult the section titled, “amplifier configuration block” for details...

  • Page 16: Integrator Reset Enable

    Integrator reset enable integrator reset enable along with the power supply monitoring feature of this amplifier, an integrator reset feature is provided. Jumper sw en enables / disables resetting of the integrator of the amplifier. With this jumper in the 1-2 position, the integrator used for the c...

  • Page 17

    Amplifier configuration block voltage mode gain setting in voltage mode, the total gain of the amplifier is determined by the components a, c, and d in the configuration block. From the description in table 2 and the schematic diagram in figure 6, the total gain can be calculated as the product of g...

  • Page 18

    Amplifier configuration block row part name function default value a r36 this resistor with d sets the first gain stage of the amplifier. The resulting gain is g 1 = d/a. 10k b r33 current loop feedback gain resistor. 1k c r22 sets the gain in voltage mode for the amplifier. The resulting gain for t...

  • Page 19

    Current mode configuration in order to set the gain of the amplifier, you need to select components d and a. These set the forward gain such that the amplifier delivers g amps/v. The equation for the forward gain of the amplifier is g = 2 d a table 3 shows recommended values g – amps / v d – ohms a ...

  • Page 20

    Do you want an integrator? First you need to determine whether you want integration or not. The capacitor e will introduce an integrator in the feedback loop in order to assure zero steady state error in current independent of load resistance and back emf. The disadvantage of using an integrator in ...

  • Page 21

    Kp = 1 ( b = 1 k) r load gain 2 0.8333 4 0.7143 6 0.6250 8 0.5556 10 0.5000 note that the gain depends on the load resistance and will not be consistent throughout the operating temperature range of the load since the load resistance increases as the load resistance gets warm. That is another reason...

  • Page 22

    Parameter value units r load 4 ohms l load 0.0001 henry with the following components for the compensation network: component purpose value units e integration gain capacitor 2.20e-008 farads b loop gain resistor 1000 ohms you can tune these values to optimize performance. A matlab and a simulink mo...

  • Page 23

    • if there is too much overshoot due to integration reduce the integral gain by increasing the capacitance of e. • you may need to increase the loop gain using b to dampen the response after selecting e. Also note that the higher the inductance the more proportional loop gain you will require and th...

  • Page 24

    Lload = .1e-3; rload = 4; % tune these in the simulink diagram or here comp_e = 22e-9; %integration capacitor - increase to reduce integral gain standard 0.05 micro comp_b = 1e3; %feedback gain resistor - variable - increase to increase loop gain then run the file again to see if the response as you...

  • Page 25: Power Supply

    The small signal matlab model. This simulation is more realistic than the matlab model. For slow systems ( system with large inductance, > .01 henry) you will need to slow the signal generator frequency in order to observe the steady state response of the system. Note that both these simulations giv...

  • Page 26: Load Connection

    Load connection the load is connected to the amplifier at this connector. Note that the each of the pins is duplicated within this connector for additional current handling capability. User connections should make use of all the pins for optimal current handling ability. The output of the amplifier ...

  • Page 27: Gnd Lug

    Load connection gnd lug the gnd lug is provided for convenience where several amplifiers are connected together (multiple channel application) and a common ground reference is needed. This is the only ground that should be treated as common between the input/output signals and the amplifier itself. ...

  • Page 28: Offset Adjustment

    Offset adjustment offset adjustment a potentiometer is provided to allow setting the output voltage / current of the amplifier to zero for zero commanded input. Turning the potentiometer to the right (clockwise) increases the offset, making the value more positive. Offset adjustment procedure the se...

  • Page 29: Current Limit Adjustment

    Offset adjustment one was placed there. Current limit adjustment current limiting allows the user to set a maximum (peak) current that the amplifier will provide to the load. The amplifier will provide current up the set current limit. Continuous currents of 7 amps are possible, while peak currents ...

  • Page 30

    Current limit adjustment current limit (amps) measured current limit output (volts) 1 0.50 2 1.00 3 1.50 4 2.00 5 2.50 6 3.00 7 3.50 max 5.00 table 8. Typical current limit settings pin number function 6 signal (0-5v) 7 gnd table 9. Current limit output pinouts. Power amplifier module user's guide 2...

  • Page 31: Status Indicator Leds

    Current limit adjustment procedure adjustment of the current limit requires a few special tools: • multimeter • small screwdriver to adjust the current limit, follow this procedure: 1. Connect the multimeter to the terminals shown in (connector j1). 2. Adjust the trimpot to the desired voltage for t...

  • Page 32: Amplifier Enable Inputs

    External fault indication making the signal suitable for directly driving and external led. Alternatively, the signal may be buffered and used as a status indicator for the connection to external control circuitry. Amplifier enable inputs the amplifier is provided with two inputs which must receive ...

  • Page 33: Command Signal

    Command signal command signal the input signal to the amplifier is a differential type input. This signal is called the reference signal, and is applied to the amplifier on the user connection header. Connections should be made at pins 4, ref- and pin 5, ref+. The amplifier measures the difference b...

  • Page 34: Installation

    Installation installation installation, mounting and information on making electrical connections to the amplifier can be found in this section. Mechanical mounting the amplifier is fitted with a series of mounting holes along two surfaces. These holes make it possible to mount the amplifier to a su...

  • Page 35: Cooling Fans

    Cooling fans cooling fans most applications of the power amplifier module will require the use of cooling fans, to maintain the amplifier at a safe operating temperature. The heatsink of the amplifier has holes tapped to accept #8 mounting hardware. Either two 1.25” fans may be used, or one 2” fan c...

  • Page 36

    Cooling fans two fans rated for 4.5 cfm or 1 rated 9 cfm or greater should suffice for most applications. Determining the dissipated power calculation of the power dissipated by the amplifier is critical to determining the amount of cooling required of the amplifier. Assuming the worst-case scenario...

  • Page 37

    Determining the required airflow for cooling determining the required airflow for cooling the power dissipated must be removed from the amplifier. This is best accomplished with the use of a fan. Calculations for the required airflow for the fan are as follows. Q cfm = 3.16 × p t f = 1.76 × p t c q ...

  • Page 38: Electrical Connections

    Determining the required airflow for cooling optimal fan based on required flow rate and enclosure selection. The user should be careful to understand that the fan will need to be mounted within the manufacturer's guidelines to ensure that the specified airflow rate is achieved. Note that the above ...

  • Page 39: Selecting A Power Supply

    Electrical connections description manufacturer supplier shorting jumpers 3m/isd 929950-00 digi-key 929950-nd selecting a power supply a power supply is required to provide electrical power to the amplifier. The size, type and capacity of the power supply are highly dependent on the application. Ope...

  • Page 40: Connecting A Single Unit

    Selecting a power supply current handling capability the power supply chosen must be able to deliver the expected power to the load, plus some additional power used by the amplifier itself. Typically, to use the amplifier at its fully rated current ability, the power supply must be capable of delive...

  • Page 41: Connecting Multiple Units

    Connecting a single unit connecting multiple units several amplifier units can be connected together to allow for multi-channel configurations. In this setup, a common ground point is often required. The ground lug should be used for this purpose. Figures 18 and 19 show two types of possible connect...

  • Page 42

    Connecting multiple units power amplifier module user's guide 41 figure 18. Multiple amplifiers connected with a single power supply. Power supply amplifier module #1 amplifier module #2 isolated power supply amplifier module #n common system gnd.

  • Page 43

    Connecting multiple units 42 power amplifier module user's guide figure 19. Multiple power supplies to drive multiple power amplifiers. Power supply #1 amplifier module #1 amplifier module #2 isolated power supply power supply #2 isolated power supply common system gnd.

  • Page 44: Appendix A

    Appendix a appendix a dimensions the following pages show the mechanical drawings for the heatsink of the power amplifier module. These drawings can be used in the fabrication of the enclosure of a mounting fixture. Power amplifier module user's guide 43.

  • Page 45

    Dimensions 44 power amplifier module user's guide.