Circuit Description
The circuit diagram of the AE20401 can be divided into several
parts, which are described here.
The digital part is based on microcontroller IC1. IC1 controls
all functions, computes the readings, and drives the LCD. The
USB port is handled by the FT230X UART-USB Bridge (IC5).
IC8 is the 2.5V reference for the ADC (analog to digital
converter) that is used to convert the analog output of the
Power Meter Module to a digital value.
The 5V digital supply comes from the linear regulator IC4. D1
protects IC4 from reverse polarity of the input voltage.
Decoupling capacitors are placed next to all ICs. Each module
has their own power regulation and decoupling capacitors on
their own boards.
Channel A/C input circuitry: the DC offset is removed from the
signal first. Then it is impedance matched and fed to the input
amplifier. D2/D3 limit the signal in case of input overload. P1*
is used to attenuate it. A high-speed comparator (IC6) with
hysteresis is then used to compare the signal against a reference
voltage. (see chapter "Adjustment" for details).
Now a 5Vpp square wave that is the same frequency as the
input signal is available which can be processed by the digital
(logic) ICs. Along with the signal from Channel B, which is
already divided by 500 in the module, it is divided by 2 by a
high speed flip-flop (IC2), then further by 8 by a 4bit counter
(IC3).
2
Summary of Contents for AE20401
Page 23: ...Finished Component Side Finished Solder Side without the LCD LCD Mounting 17 ...
Page 31: ...Operation Functions Menu Structure 25 ...
Page 37: ...31 Example 1 noise Example 2 one signal superimposed on another ...
Page 50: ...Circuit Diagram Part 1 2 44 ...
Page 51: ...Part 2 2 45 ...
Page 63: ... Nr of valid counts depends on range 57 ...
Page 64: ...ASCEL ELECTRONIC www ascel electronic de 2015 ...