Connecting an IR receiver to Transistor for current control
Look closely at figure 4 of the data sheet. Do you notice how the output is essentially just an NPN transistor and a resistor? Also notice that the output goes low when modulated IR is detected.

The simplest way to do what you want (light an LED when IR is detected) is to change your circuit slightly. Instead of using one or more NPN transistors, use a single PNP. A 2N3906 is a reasonable choice for what you're doing. Also notice that the LED forward voltage is not 3.3 to 5 volts as you show - it is 3.3 to 4 volts, so you need a series resistor to limit the current through the LED. Furthermore, connecting your 4 LEDs in parallel (which is what I think you mean by "matrix" is potentially a bad idea. You are better off connecting each with its own current limiting resistor.

So, taking all this into account,







simulate this circuit &ndash; Schematic created using CircuitLab

will (probably) do the job. 

There is a potential problem. The output of the sensor is specified as 0.2 to 0.4 volts, but the current it can handle at those levels is not specified. The circuit shown will attempt to drive about 8 mA through the base of the transistor. If the sensor will not handle this, the transistor may not turn on fully, and the LEDs will be somewhat dim. If this is the case, your 2-transistor circuit, with two modifications, will be OK.

The first modification I'd recommend is changing the collector resistor of the first NPN to 470 ohms. The second, of course, is adding a current-limit resistor to each LED.

For LED voltages in the range of 3.3 to 4 volts, the current for this circuit will run about 10 to 15 mA, which is a comfortable range for LEDs with a maximum current of 20 mA.