Recognition technique

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Recognition technique

To identify the connected lamp, the power must be evaluated by measuring both the lamp

voltage and current.

In this way, by multiplying these measurements, it is possible to obtain the lamp power:

Equation 13

With the evaluation board based on STMicroelectronics' ST7FLIT19BF1 MCU and L6382D5

driver, the lamp power measurements can be easily calculated. Our proposal is based on a

transition mode (TM). In the transition mode operation the boost converter works with a fixed

proportional at the load power as shown in the following relationship:

Equation 14

Where:

●

●

L is the PFC inductor value

●

●

This technique provides a key advantage of obtaining the lamp power information by directly

reading the PFC conduction time without multiplier evaluations in the board.

When the mains is switched ON the microcontroller performs a measurement on the AC

input voltage. After this phase it starts the half-bridge. The PFC is activated during this initial

phase to distinguish the family type and a cathode resistance measurement is performed to

select the lamp type.

After this selection, the preheating phase is performed until the ignition phase turns the

lamp on.

After the ignition the connected lamp is recognized and starts the run phase.

Using the described technique it is simple to calculate the lamp power. Experimental results

have confirmed this data.

P

lamp

V

lamp

I

lamp

⋅

=

T

ON

2LP

o

⋅⋅

V

2

inr

----------------------------

=