| 摘要 |
An apparatus for and a method of measuring, in real-time, and indicating power consumption of a product powered by a switching mode power supply (SMPS). Power is supplied to the product through a transformer (T11) having a predetermined primary coil inductance (Lp), wherein a current (Ip) of a primary coil of the transformer (T11) is turned ON and OFF by pulse-width modulation to supply the power to the electronic device. A drive voltage (Vi) across the primary coil is monitored and a pulse waveform having a first level corresponding to an ON time (ton) of the current (Ip) in the primary coil and a second level corresponding to an OFF time (toff) of the current (Ip) in the primary coil is developed. Power consumption (P) is calculated based on the drive voltage (Vi), the ON time (ton) of the current (Ip) in the primary coil, the predetermined primary coil inductance (Lp), and a switching frequency (1/T) of a pulse width modulator of the SMPS. <IMAGE> |
