Contents
- 1 What is short circuit output current?
- 2 What does current limit of the LDO mean and how is it measured?
- 3 How does current flow in a short circuit?
- 4 Where does current go in a short circuit?
- 5 How is LDO calculated?
- 6 How does the current limit in an LDO work?
- 7 What is the dropout voltage of a LDO regulator?
- 8 When does a dropout voltage in a circuit occur?
What is short circuit output current?
The current into an output terminal when the output is short-circuited to ground with input conditions applied that, according to the product specification, will establish the output logic furthest from ground potential.
What does current limit of the LDO mean and how is it measured?
Current limit in an LDO is defined by establishing an upper boundary for the current supplied. In this internal circuit, the LDO measures the output voltage for feedback but also measures a scaled mirror of the output current against the internal reference (IREF).
How is input current calculated in LDO?
Suppose that you want to use an LDO regulator at VOUT = 1.2 V and IOUT = 500 mA. In this case, the maximum dropout voltage is 150 mV. Hence, Minimum input voltage = 1.2 V + 0.15 V = 1.35 V Therefore, input voltage must be 1.35 V or higher, and VBIAS must be over 3.3 V.
How does current flow in a short circuit?
A short circuit implies that the two terminals are externally connected with resistance R=0 , the same as an ideal wire. This means there is zero voltage difference for any current value. This means that zero current can flow between the two terminals, regardless of any voltage difference.
Where does current go in a short circuit?
During a short circuit, the current is maximum and flowing through the conductor. The resistance of conductor is as low as 0.
How does current limiting circuit work?
The circuit for the power supply current limiter uses a sense resistor placed in series with the emitter of the output pass transistor. This starts to pull the voltage on the base of the transistor down, thereby limiting the current that can be drawn.
How is LDO calculated?
The maximum junction temperature of an LDO can be calculated from its power consumption and thermal resistance using Equations 1 and 2. For example, suppose that VIN=1.5 V, VOUT=1 V, IOUT=200 mA, IB=20 μA, PD=0.6 W, and Ta=60°C. Then, the maximum junction temperature of the LDO can be calculated as follows.
How does the current limit in an LDO work?
Current limit in an LDO is defined by establishing an upper boundary for the current supplied. Unlike a constant current source, LDOs supply current on demand but can also control the total power regulated. Current limiting is achieved through internal circuitry controlling the output stage transistors inside the LDO.
How does the LDO circuit affect the transient response?
LDO circuit affect the overall transient response of the LDO. The crossover frequency affects the settling time of the linear regulator circuit, where the settling time is the time elapsed from the initial onset of the load transient to the time where the output voltage returns to within a few per-cent of a steady-state value.
What is the dropout voltage of a LDO regulator?
The dropout voltage of the TPS76733 is typically 350 mV at 1 A. Thus, the LDO regulator begins dropping out at 3.65-V input voltage; the range of the dropout region is between approximately 2-V and 3.65V input voltage. Below this, the device is nonfunctional.
When does a dropout voltage in a circuit occur?
Dropout voltage is the input-to-output differential voltage at which the circuit ceases to regulate against further reductions in input voltage; this point occurs when the input voltage approaches the output voltage.