op#amp&internal&circuits¤t&measurement&with&sense#transistor&...
TRANSCRIPT
Op-‐Amp internal circuits
Bipolar (BJT) or MOSFET ?
N-‐ or P-‐Input for Op-‐Amp ?
Comparator, Opamp, OTA ?
Comparator, Opamp, OTA ?
Basic use of OpAmps
Comparator with N-‐device as input
Simple 1-‐stage CMOS -‐ OTA
gm – compare BJT / MOSFET
2-‐stage MOSFET – Comparator
2-‐stage MOSFET – OTA „Miller OTA“
Bode diagram of Miller OTA
AC-‐SimulaMon of a 2-‐stage Miller OTA
AC-‐analysis: Check Stability with Transient Analysis
w/l scaling for 2-‐stage MOSFET -‐ comparator
How to avoid/to minimize offset of a comparator
Random Offset – Monte Carlo SimulaMon
Improve the offset with larger devices
MOSFET -‐ comparator with push-‐pull current output
MOSFET -‐ comparator (OTA) with cascode output
MOSFET -‐ OTA: Folded cascode
Folded cascode OTA – frequency response
Folded Cascode example with p-‐channel input
Bipolar (BJT) -‐ comparator
Comparator with P-‐device as input
pnp-‐input Comparator: Input voltage range
Darlington inputs
pnp darlington comparator: current measurement
P-‐input MOS comparator: logic input buffer with special input specificaMon range
npn-‐input comparator: open load voltage measurement
EmiZer / Source Follower as Output Stage
Opamp as buffer
npn-‐input Opamp as buffer (voltage follower)
Opamp with push-‐pull output
MOSFET -‐ Push-‐Pull Output Stage
N-‐input MOSFET comparator with hysteresis
npn-‐input, otherwise MOSFET comp.: voltage measurement
Bip/MOSFET Comparator with Hysteresis with clamp voltage (vr3) to avoid bipolar saturaMon
CalculaMon of hysteresis of bipolar comparator
Comparator with emiZer-‐input
pnp with emiZer -‐ input
P-‐channel source-‐input comparator
Current measurement with Shunt-‐Resistor
Current Measurement with Shunt-‐Resistor: emiZer-‐input-‐comparator, uses ΔVBE principle
Current Measurement with Sense-‐Transistor Shunt-‐resistance in series to sense-‐cell
Current Measurement with Sense-‐Transistor Sense-‐cell with Shunt-‐Res., Reference-‐Current with Reference-‐Resistor
Current Comparator
High Voltage Input -‐ Current Comparator with low voltage devices
Acknowledgments
Dr. Heinz ZiZa
Infineon Technologies Austria