Analog topologies abound for changing present to voltage, voltage to present, voltage to frequency, and frequency to voltage, amongst different conversions.
Determine 1 joins the flock whereas singing a considerably totally different tune. This present, voltage, and energy (IVW) DC energy converter multiplies present by voltage to sense wattage. Right here’s the way it will get off the bottom.
Determine 1 The “I*V = W” converter contains voltage-to-frequency conversion (U1ab & A1a) with frequency (F) of 2000 * Vload, adopted by frequency-to-voltage conversion (U1c & A1b) with Vw = Iload * F / 20000 = (Iload * Vload) / 10 = Watts / 10 the place Vload < 33 V and Iload < 1.5 A.
Wow the engineering world together with your distinctive design: Design Concepts Submission Information
The essential topology of the IVW converter contains a voltage-to-frequency converter (VFC) cascaded with a frequency-to-voltage converter (FVC). U1ab and A1a, mixed with the encompassing discretes (Q1, Q2, Q3, and so on.), make a VFC just like the one described on this earlier Design Thought, “Voltage inverter design concept transmogrifies right into a 1MHz VFC”
The U1ab, A1a, C2, and so on., VFC kinds an inverting cost pump suggestions loop that actively balances the 1 µA/V present via R2. Every cycle of the VFC deposits a cost of 5v * C2, or 500 picocoulombs (pC), onto integrator capacitor C3 to provide an F of 2 kHz * Vload (= 1 µA / 500 pC) for the management sign enter of the FVC change U1c.
The opposite enter to the U1c FVC is the -100 mV/A current-sense sign from R1. This combo forces U1c to pump F * -0.1 V/amp * 500 pF = -2 kHz * Vload * 50 pC * Iload into the enter of the A1b inverting integrator.
The melodious result’s:
Vw = R1 * Iload * 2000 * Vload * R6 * C6
or,
Vw = Iload * Vload * 0.1 * 2000 * 1 MΩ * 500 pF = 100 mV/W.
The R6C5 = 100-ms integrator time fixed gives >60-dB of ripple attenuation for Vload > 1-V and a low noise 0- to 5-V output appropriate for consumption by a typical 8- to 10-bit decision ADC enter. Diode D1 gives hearth insurance coverage for U1 in case Vload will get shorted to floor.
Stephen Woodward’s relationship with EDN’s DI column goes again fairly a good distance. Over 100 submissions have been accepted since his first contribution again in 1974.
Associated Content material
- Voltage inverter design concept transmogrifies right into a 1MHz VFC
- A simulated 100-MHz VFC
- A easy, correct, and environment friendly cost pump voltage inverter for $1 (in singles)
- 100-MHz VFC with TBH present pump
The publish Amps x Volts = Watts appeared first on EDN.
