Comparator Window Settings

Conventional window comparators suffer interaction between the width and the center of the window; this makes adjusting these parameters time consuming. By using a precision dual 100uA current reference (REF200), this interaction is eliminated. The width of the comparator window is determined by the reference current and the value of P1: V = 100uA * 20k. The DC voltage of the window center is set by the % rotation of the potentiometer P1. With the pot at its center (50%), the center of the comparator window is at zero volts– thus the window is +/-1V. The window center adjustment is illustrated below. (Circuit is created by Neil P. Albaugh  TI- Tucson)

Comparator Window Settings circuit:

comparator window settings-blog

Online Simulation of the Comparator Window Settings Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud and analyze the circuit yourself, or watch our tutorial video!  

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

Laser Energy Meter

 

An IVC102 switched integrator is also capable of integrating the output of a very fast detector. By storing the energy of a fast detector current pulse on its own capacitance (or on additional capacitance), this energy can then be transfered to the integrator feedback capacitor where it is held until it is sampled and the integrator can then be reset, awaiting the next pulse. Thus laser energy can be measured on a pulse- by- pulse basis. Needless to say, It is necessary to sync the integrator timing with the laser Q- switch. The simulated detector output pulse was 10mA peak with a 10ns width. Charge is stored on Cs until it is transfered when S1 closes. To prevent droop error due to shunt resistance Rs and the input bias current of U1, S1 should be closed a few microseconds after the laser pulse. The IVC102 can integrate a positive- output or negative- output detector. Lower sensitivity can be achieved by paralleling C2, C3, or an external capacitance. Bypass capacitors are not shown.  (Circuit is created by Neil P. Albaugh  TI- Tucson)

 Laser Energy Meter circuit:

Laser Energy meter-blog

Online Simulation of the Laser Energy Meter Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit yourself, or watch our tutorial video!

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

DAC Interface Circuit

This “DAC Interface”  circuit is a precision buffer amplifier for a DAC output. It is scaled to provide a 10V output @ 10mA with a +1V input voltage. This type of current source can be very useful in industrial interface applications.  A R-R output op amp with an input common-mode
range that includes its negative supply rail, such as an OPA251, is required for single- supply operation.  An external NPN transistor  is used to off- load the circuit power dissipation from the precision op amp U1. Re- scaling this circuit with other transistors can result in output current capability of a many amps. (Circuit is created by Neil P. Albaugh  TI – Tucson)

DAC Interface Circuit:

DAC interface-blog

 

Online Simulation of the DAC Interface Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit yourself, or  watch our tutorial video!

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

 

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

Comparator With AC Hysteresis

Using AC hysteresis solves the threshold offset problem caused by conventional DC hysteresis. Place a small capacitor to feed back the output edge transition into the comparator non- inverting input to provide momentary positive feedback. This sharpens the comparator response as well as reducing the tendency to “chatter” at the switching point. If the RC time constant of R1C1 is << the waveform period, the comparator trip point hysteresis will have settled back to 0V by the time the next threshold- crossing takes place. (Circuit is created by Neil P. Albaugh  TI- Tucson)

Comparator With AC Hysteresis circuit:

comparator with AC hysteresis3

 

Online Simulation of a Comparator with AC Hysteresis circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

 Click here to invoke TINACloud  and analyze the circuit yourself, or  watch our tutorial video!

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

Zoom Amplifier

This “unusual zoom amplifier circuit” allows you to “zero out” a DC voltage and then amplify a small AC signal which is superimposed on the much larger DC level. When switch SW1 is closed, both INA128 inputs see the same AC + DC level and its high common- mode rejection results in zero volts output. When SW1 is opened, the DC level is stored on C1 but now the AC signal is applied to only the inverting input where it is amplified by a factor of 1000x. The droop rate of C1 depends on the leakage of SW1 and the input bias current of U1.Using a glass reed relay and an INA116 (Ib = 5fA typ), extremely low droop rate can be achieved. A high insulation resistance dielectric capacitor is necessary– teflon, polystyrene, etc. (Circuit is created by Neil P. Albaugh  TI- Tucson)

Zoom amplifier circuit:

Zoom amplifier-blog

 

Online Simulation of a Zoom  Amplifier Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit yourself, or  watch our tutorial video!

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

Current Shunt Amplifier

This current shunt monitor circuit allows a current measurement to be made by measuring the voltage drop across a shunt resistor in the “high side” of a power supply. The INA193 is capable of operating with a common- mode voltage of up to +80V and its CMV range is not a function of
its supply voltage.  The INA193 provides a differential voltage gain of 20V/V and its recommended full- scale input  voltage is 100mV.  An INA194 provides a gain of 50V/V and an INA195 provides a gain of 100V/V. R1 & R2 together with C2, C3, & C4 provide differential and common-mode filtering and are recommended for switching power supplies. The two resistors should be carefully matched (1% tolerance) as well as capacitors C3 & C4 (5% or better tolerance). Resistors of 100 ohms will give a gain error of slightly under 2%. (Circuit is created by Neil P. Albaugh,  TI – Tucson)

Current Shunt Amplifier circuit:

Current shunt amplifier-blog

Online Simulation of the Current Shunt Amplifier Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit yourself, or  watch our tutorial video!

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

Proportional- Integral Temperature Control

A high- accuracy temperature control amplifier can be realized with a proportional- integral amplifier response; the integrator function drives the steady- state error to zero.  An autozero instrumentation amplifier INA326 achieves very low offset and drift as well as virtually eliminating the loop error due to 1/f noise. R6 is used simply to provide a feedback path during a DC analysis. This circuit requires an overall feedback path (TEC, etc) to achieve a steady-state operating point. This amplifier allows temperature control loop stability within in a few tens of milli- degrees. Bypass capacitors are not shown. This circuit can be used with a DRV593 or an OPA569 TEC driver circuit. (Circuit is created by Neil P. Albaugh  TI – Tucson)

     Proportional- Integral Temperature Control circuit:

proportional integral temperature control-blog

 

Online Simulation of the Proportional- Integral Temperature Control Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit yourself, or  watch our tutorial video!

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

Capacitance Multiplier

A “capacitance multiplier” circuit can increase the effective value of a small capacitor C1 to a much larger value. The capacitance  seen at Vout is: Cout = C1 * R1/R3. Note that this circuit is only for a ground- referenced capacitor. Rs = R3. The output capacitance can be verified by placing an AC source in series with a resistor tied to Vout and running an AC frequency  response analysis. As seen in the result below, the 100pF capacitor has been multiplied by 1,000. Bypass capacitors are not shown.  (From a NSC app note) Circuit is created by Neil P. Albaugh  TI – Tucson

Capacitance Multiplier circuit: capacitance multiplier for blog

Online Simulation of the Capacitance Multiplier Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud  and analyze the circuit yourself, or  watch our tutorial video!

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

OPA569 Laser Driver

The “OPA569 Laser Driver” circuit provides voltage- controlled constant- current biasing of a grounded- anode laser diode by using a negative supply voltage and a positive control voltage.  As shown, the OPA569 op amp provides an output current of 500mA per volt input. Output is current- limited to 2A by R2. Frequency compensation is provided by C3 R3. This circuit takes advantage of the unique topology of the OPA569; it does not require a shunt resistor to measure its output current. This amplifier provides an output monitor current from pin 19 that is 1/475 th of its output current. This current is used as negative feedback to the amplifier’s inverting input (pin 5).  A constant- current output is derived by this feedback.
Since no shunt resistor is required to measure output current, there is no reduction in output voltage compliance due to shunt resistor voltage drop and this circuit can swing its output voltage very close to its supply rail. This increases efficiency and reduces heat sinking requirements. In fact, supply voltage can be reduced to 3.3V  for most laser diodes.
The OPA569 features both a Current Limit (pin 4) and a Thermal Overtemp (pin 7) flag. These flags can be used to protect the amplifier and the Enable (pin 8) can be used to digitally control its status. (Circuit is created by Neil P. Albaugh,  TI – Tucson)

OPA569 Laser Driver Circuit

 OPA569 Laser Driver for blog2

Online Simulation of the OPA569 Laser Driver Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud and analyze the circuit or watch our tutorial video.

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS

Universal Voltage Reference

“This universal voltage reference circuit”- can provide a reference voltage that is continuously adjustable between -10V and +10V. If a REF02 is substituted for the  REF102 shown here, the output range will be -5V to +5V.The circuit uses both an op amp inverting gain path and a non- inverting  gain path simultaneously.  A potentiometer controls the ratio of these two gain paths. With the potentiometer wiper arm grounded,  U1 operates as an ordinary inverting amplifier with a gain of -1V/V. When the wiper arm is rotated to the other end of the potentiometer,  however, there is an additional gain path of +2V/V in addition to the -1V/V path. The resulting sum is a gain of +1V/V. At 50% rotation  (the wiper arm is exactly centered) the non- inverting gain path drops to +1V/V— cancelling the -1V/V gain entirely.  The output is then 0V. P1 should be a good quality potentiometer with high resolution and a good temperature coefficient.  Fortunately, the TC match of the resistance ratios of a potentiometer is much lower than its absolute resistance TC. (Circuit is created by Neil P. Albaugh  TI- Tucson)
  universal voltage reference for blog

Universal Voltage Reference

Online Simulation of the Universal Voltage Reference Circuit

The great feature of the TINA circuit simulator that you can analyze this circuit immediately with TINACloud the online version of TINA. Of course you can also run this circuit in the off-line version of TINA.

Click here to invoke TINACloud and analyze the circuit.

You can send this link to any TINACloud customers and they can immediatelly load it by a single click and then run using TINACloud.

Michael Koltai
www.tina.com

Share and Enjoy

  • Facebook
  • Twitter
  • Delicious
  • LinkedIn
  • StumbleUpon
  • Add to favorites
  • Email
  • RSS