Photo-receiver arrangement
A photo-receiver arrangement includes a photo-sensor that captures light being incident thereon within a predetermined range of light intensity values. The photo-sensor also converts the captured incident light into a first electrical signal. A pre-scaler is connected to an output of the photo-sensor for producing a second scaled electrical signal based on and corresponding to said first electrical signal input into the pre-scaler; and a preamplifier is connected to an output of the pre-scaler for amplifying said second scaled electrical signal input into the preamplifier. The preamplifier has a dynamic range of at least substantially linear gain. The pre-scaler and the preamplifier are designed in a mutually matching configuration such that the second scaled electrical signal falls within the said dynamic range of the preamplifier for any light intensity value falling into said predetermined range of light intensity values.
1. A photo-receiver arrangement, comprising
a photo-sensor that captures light being incident thereon within a predetermined range of light intensity values, and converts the captured incident light into a first electrical signal;
a pre-scaler connected to the photo-sensor to produce a second scaled electrical signal based on and corresponding to said first electrical signal input into the pre-scaler, wherein the second scaled electrical signal is produced by the pre-scaler using a variable scaling factor which is dependent on the first electrical signal; and
a preamplifier connected to an output of the pre-scaler to amplify the second scaled electrical signal input into the preamplifier, the preamplifier having a dynamic range of at least substantially linear gain;
wherein the pre-scaler and the preamplifier are designed in a mutually matching configuration such that the second scaled electrical signal falls within the said dynamic range of the preamplifier for any light intensity value falling into said predetermined range of light intensity values, and wherein the second scaled electrical signal is produced by the pre-scaler independently of the preamplifier.
2. The photo-receiver arrangement according to claim 1 , wherein the photo-sensor is an infrared sensor, and the pre-scaler and the preamplifier are designed in matching relationship with the infrared sensor.
3. The photo-receiver arrangement according to claim 1 , wherein the pre-scaler is designed such as to perform a scaling of said first electrical signal with a set of discrete scaling factors.
4. The photo-receiver arrangement according to claim 3 , wherein the pre-scaler is designed such that its scaling factor is determined by said first electrical signal.
5. The photo-receiver arrangement according to claim 1 , wherein the pre-scalar comprises a programmable current mirror.
6. The photo-receiver arrangement according to claim 5 , wherein the pre-scaler comprises a current sensing circuit, the current sensing circuit being connected to said programmable current mirror for controlling the same.
7. The photo-receiver arrangement according to claim 6 , wherein the current sensing circuit is an A/D converter.
8. The photo-receiver arrangement according to claim 5 , wherein the programmable current mirror is implemented by MOS or BJT transistors.
9. The photo-receiver arrangement according to claim 1 , wherein the preamplifier is a transimpedance amplifier comprising an operational amplifier, a feedback resistor and a feedback capacitor connected between the output and the negative input of the operational amplifier.
10. The photo-receiver arrangement according to claim 1 , wherein the photo-sensor, the pro-scaler, and the preamplifier are designed in a single-ended configuration.
11. The photo-receiver arrangement according to claim 1 , wherein the photo-sensor, the pre-scaler and the preamplifier are designed in a differential or pseudo differential configuration.