Abstract: Rail splitting is creating an artificial virtual Ground as a reference voltage. It is used to set the signalto match the op amp's "sweet spot." An op amp has the most linear- and distortion-free qualities at that sweetspot. Typically, the sweet spot occurs near the center between the single power rail and Ground. In the case ofa number of signals, the virtual Ground can control channel DC errors when multiplexing or switching thesignals.
What would happen if someone connected 24V to your12V circuits? If the power and Ground lines were inadvertentlyreversed, would the circuits survive? Does yourapplication reside in a harsh environment, where the inputsupply can ring very high or even below Ground? Evenif these events are unlikely, it only takes one to destroya circuit board.
The above title is not happenstance and was arrived at afterconsiderable deliberation. As a linear IC manufacturer, it isour goal to encourage users to design and build switchingregulators. A problem is that while everyone agrees thatworking switching regulators are a good thing, everyonealso agrees that they are difficult to get working. Switchingregulators, with their high efficiency and small size, areincreasingly desirable as overall package sizes shrink.Unfortunately, switching regulators are also one of themost difficult linear circuits to design. Mysterious modes,sudden, seemingly inexplicable failures, peculiar regulationcharacteristics and just plain explosions are commonoccurrences. Diodes conduct the wrong way. Things gethot that shouldn’t. Capacitors act like resistors, fusesdon’t blow and transistors do. The output is at Ground, andthe Ground terminal shows volts of noise.
Demonstration circuit 1562A is an engineering toolto design and evaluate the LTC699X-X family ofTimerBlox circuits. The center section of the boardcontains a pre-configured TimerBlox function.DC1562A comes in twelve timing function variationsas outlined in Table 1.Surrounding the center board is a ”playGround”prototyping area. The prototyping area has padsfor Dip-8, S8, MS8, or S6 packages with breadboarding connections to each pin and two convenientpower buses and Ground bus surrounding theentire area. This area is for conditioning signals tocontrol the timer function and for adding loads controlled in time.
The ISO7220 and ISO7221 are dual-channel digital isolators. To facilitate PCB layout, the channels are orientedin the same direction in the ISO7220 and in opposite directions in the ISO7221. These devices have a logic inputand output buffer separated by TI’s silicon-dioxide (SiO2) isolation barrier, providing galvanic isolation of up to4000 V. Used in conjunction with isolated power supplies, these devices block high voltage, isolate Grounds, andprevent noise currents on a data bus or other circuits from entering the local Ground and interfering with ordamaging sensitive circuitry.
Prakash Rashinkar has over 15 years experience in system design and verificationof embedded systems for communication satellites, launch vehicles and spacecraftGround systems, high-performance computing, switching, multimedia, and wirelessapplications. Prakash graduated with an MSEE from Regional Engineering College,Warangal, in India. He lead the team that was responsible for delivering themethodologies for SOC verification at Cadence Design Systems. Prakash is anactive member of the VSIA Functional Verification DWG. He is currently Architectin the Vertical Markets and Design Environments Group at Cadence.
Prakash Rashinkar has over 15 years experience in system design and verificationof embedded systems for communication satellites, launch vehicles and spacecraftGround systems, high-performance computing, switching, multimedia, and wirelessapplications. Prakash graduated with an MSEE from Regional Engineering College,Warangal, in India. He lead the team that was responsible for delivering themethodologies for SOC verification at Cadence Design Systems. Prakash is anactive member of the VSIA Functional Verification DWG. He is currently Architectin the Vertical Markets and Design Environments Group at Cadence.
