Datasheet IL300 (Vishay) - 2
| Manufacturer | Vishay |
| Description | Linear Optocoupler, High Gain Stability, Wide Bandwidth |
| Pages / Page | 11 / 2 — IL300. OPERATION DESCRIPTION. K3-TRANSFER FAIN LINEARITY. PHOTODIODE. LED … |
| File Format / Size | PDF / 191 Kb |
| Document Language | English |
IL300. OPERATION DESCRIPTION. K3-TRANSFER FAIN LINEARITY. PHOTODIODE. LED (LIGHT EMITTING DIODE). APPLICATION CIRCUIT
Model Line for this Datasheet
- IL300 IL300-DEFG IL300-DEFG-X001 IL300-DEFG-X006 IL300-DEFG-X007 IL300-DEFG-X007T IL300-DEFG-X009 IL300-DEFG-X009T IL300-DEFG-X016 IL300-DEFG-X017 IL300-DEFG-X017T IL300-E IL300-E-X001 IL300-E-X006 IL300-E-X007T IL300-E-X009T IL300-E-X017T IL300-EF IL300-EF-X001 IL300-EF-X006 IL300-EF-X007 IL300-EF-X007T IL300-EF-X009 IL300-EF-X009T IL300-EF-X016 IL300-EF-X017 IL300-EF-X017T IL300-F IL300-F-X001 IL300-F-X006 IL300-F-X007 IL300-F-X009 IL300-F-X009T IL300-F-X016 IL300-F-X017 IL300-F-X017T IL300-F-X019 IL300-F-X019T IL300-X001 IL300-X006 IL300-X007 IL300-X007T IL300-X009 IL300-X009T IL300-X016 IL300-X017
Text Version of Document
IL300
www.vishay.com Vishay Semiconductors
OPERATION DESCRIPTION
K3-TRANSFER FAIN LINEARITY
A typical application circuit (figure 1) uses an operational The percent deviation of the transfer gain, as a function of amplifier at the circuit input to drive the LED. The feedback LED or temperature from a specific transfer gain at a fixed photodiode sources current to R1 connected to the inverting LED current and temperature. input of U1. The photocurrent, IP1, will be of a magnitude to satisfy the relationship of (IP1 = VIN/R1).
PHOTODIODE
The magnitude of this current is directly proportional to the A silicon diode operating as a current source. The output feedback transfer gain (K1) times the LED drive current current is proportional to the incident optical flux supplied (VIN/R1 = K1 x IF). The op-amp will supply LED current to by the LED emitter. The diode is operated in the photovoltaic force sufficient photocurrent to keep the node voltage (Vb) or photoconductive mode. In the photovoltaic mode the equal to Va. diode functions as a current source in parallel with a forward The output photodiode is connected to a non-inverting biased silicon diode. voltage follower amplifier. The photodiode load resistor, R2, The magnitude of the output current and voltage is performs the current to voltage conversion. The output dependent upon the load resistor and the incident LED amplifier voltage is the product of the output forward gain optical flux. When operated in the photoconductive mode (K2) times the LED current and photodiode load, the diode is connected to a bias supply which reverse R2 (VO = IF x K2 x R2). biases the silicon diode. The magnitude of the output Therefore, the overall transfer gain (V current is directly proportional to the LED incident optical O/VIN) becomes the ratio of the product of the output forward gain (K2) times the flux. photodiode load resistor (R2) to the product of the feedback transfer gain (K1) times the input resistor (R1). This reduces
LED (LIGHT EMITTING DIODE)
to An infrared emitter constructed of AlGaAs that emits at V 890 nm operates efficiently with drive current from 500 μA to O/VIN = (K2 x R2)/(K1 x R1). 40 mA. Best linearity can be obtained at drive currents The overall transfer gain is completely independent of the between 5 mA to 20 mA. Its output flux typically changes by LED forward current. The IL300 transfer gain (K3) is -0.5 %/°C over the above operational current range. expressed as the ratio of the output gain (K2) to the feedback gain (K1). This shows that the circuit gain
APPLICATION CIRCUIT
becomes the product of the IL300 transfer gain times the ratio of the output to input resistors VO/VIN = K3 (R2/R1). VCC 1 IL300 8
K1-SERVO GAIN
Va + + R3 The ratio of the input photodiode current (IP1) to the LED Vin U1 2 7 current (I K2 V F) i.e., K1 = IP1/IF. Vb K1 CC - IF - V
K2-FORWARD GAIN
CC 3 6 VCC U2 Vout The ratio of the output photodiode current (I V P2) to the LED C 4 5 + current (IF), i.e., K2 = IP2/IF. lp1 R2 R1 lp2
K3-TRANSFER GAIN
The transfer gain is the ratio of the forward gain to the servo gain, i.e., K3 = K2/K1. Fig. 1 - Typical Application Circuit Rev. 1.8, 02-Jun-14
2
Document Number: 83622 For technical questions, contact: optocoupleranswers@vishay.com THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
www.vishay.com Vishay Semiconductors
OPERATION DESCRIPTION
K3-TRANSFER FAIN LINEARITY
A typical application circuit (figure 1) uses an operational The percent deviation of the transfer gain, as a function of amplifier at the circuit input to drive the LED. The feedback LED or temperature from a specific transfer gain at a fixed photodiode sources current to R1 connected to the inverting LED current and temperature. input of U1. The photocurrent, IP1, will be of a magnitude to satisfy the relationship of (IP1 = VIN/R1).
PHOTODIODE
The magnitude of this current is directly proportional to the A silicon diode operating as a current source. The output feedback transfer gain (K1) times the LED drive current current is proportional to the incident optical flux supplied (VIN/R1 = K1 x IF). The op-amp will supply LED current to by the LED emitter. The diode is operated in the photovoltaic force sufficient photocurrent to keep the node voltage (Vb) or photoconductive mode. In the photovoltaic mode the equal to Va. diode functions as a current source in parallel with a forward The output photodiode is connected to a non-inverting biased silicon diode. voltage follower amplifier. The photodiode load resistor, R2, The magnitude of the output current and voltage is performs the current to voltage conversion. The output dependent upon the load resistor and the incident LED amplifier voltage is the product of the output forward gain optical flux. When operated in the photoconductive mode (K2) times the LED current and photodiode load, the diode is connected to a bias supply which reverse R2 (VO = IF x K2 x R2). biases the silicon diode. The magnitude of the output Therefore, the overall transfer gain (V current is directly proportional to the LED incident optical O/VIN) becomes the ratio of the product of the output forward gain (K2) times the flux. photodiode load resistor (R2) to the product of the feedback transfer gain (K1) times the input resistor (R1). This reduces
LED (LIGHT EMITTING DIODE)
to An infrared emitter constructed of AlGaAs that emits at V 890 nm operates efficiently with drive current from 500 μA to O/VIN = (K2 x R2)/(K1 x R1). 40 mA. Best linearity can be obtained at drive currents The overall transfer gain is completely independent of the between 5 mA to 20 mA. Its output flux typically changes by LED forward current. The IL300 transfer gain (K3) is -0.5 %/°C over the above operational current range. expressed as the ratio of the output gain (K2) to the feedback gain (K1). This shows that the circuit gain
APPLICATION CIRCUIT
becomes the product of the IL300 transfer gain times the ratio of the output to input resistors VO/VIN = K3 (R2/R1). VCC 1 IL300 8
K1-SERVO GAIN
Va + + R3 The ratio of the input photodiode current (IP1) to the LED Vin U1 2 7 current (I K2 V F) i.e., K1 = IP1/IF. Vb K1 CC - IF - V
K2-FORWARD GAIN
CC 3 6 VCC U2 Vout The ratio of the output photodiode current (I V P2) to the LED C 4 5 + current (IF), i.e., K2 = IP2/IF. lp1 R2 R1 lp2
K3-TRANSFER GAIN
The transfer gain is the ratio of the forward gain to the servo gain, i.e., K3 = K2/K1. Fig. 1 - Typical Application Circuit Rev. 1.8, 02-Jun-14
2
Document Number: 83622 For technical questions, contact: optocoupleranswers@vishay.com THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
