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Friday, April 10, 2020

CD4060 Binary Counter Divider Oscillator

The CD4020BC, CD4060BC are 14-stage ripple carry binary counters, and the CD4040BC is a 12-stage ripple carry binary counter. The counters are advanced one count on the negative transition of each clock pulse. The counters are reset to the zero state by a logical "1" at the reset input independent of clock.

CD4040BC, 12-Stage Ripple Carry Binary Counters
CD4060BC, 14-Stage Ripple Carry Binary Counters


CD4060 - 14-Stage Ripple Carry Binary Counters
you can also use a crystal between pin 10 and 11 with two caps 22pF from 10, 11 to gnd and a 10M resistor between 10 and 11 in place of R C network for more precision.

Thursday, April 09, 2020

TDA5145 Brushless DC motor drive circuit

TDA5145 is a bipolar integrated circuit used to drive3-phase brushless DC motors in full-wave mode. The device is sensorless (saving of 3 hall-sensors) using the back-EMF sensing technique to sense the rotor position.It includes bidirectional control, brake function and has a special circuit built-in to reduce the EMI (soft switching output stages)

TDA5145 Brushless DC motor drive circuit

TDA5145 offers a sensorless three phase motor drive function. It is unique in its combination of sensorless motor drive and full-wave drive. The TDA5145 offers protected outputs capable of handling high currents and can be used with star or delta connected motors. It can easily be adapted for different motors and applications.

TDA5145 Brushless DC motor drive circuit

Full-wave driving of a three phase motor requires three push-pull output stages. In each of the six possible states two outputs are active, one sourcing (H) and one sinking(L). The third output presents a high impedance (Z) to the motor, which enables measurement of the motor back-EMF in the corresponding motor coil by the EMF comparator at each output. The commutation logic is responsible for control of the output transistors and selection of the correct EMF comparator. In Table 1 the sequence of the six possible states of the outputs has been depicted.

The zero-crossing in the motor EMF (detected by the comparator selected by the commutation logic) is used to calculate the correct moment for the next commutation,that is, the change to the next output state. The delay is calculated (depending on the motor loading) by the adaptive commutation delay block.

Thursday, April 02, 2020

LM311 - Voltage Comparator

The LM111, LM211 and LM311 are voltage comparators that have input currents nearly a thousand times lower than devices like the LM106 or LM710. They are also designed to operate over a wider range of supply voltages: from standard ±15V op amp supplies down to the single 5V supply used for IC logic.

LM311 - Voltage Comparator

LM311 - Voltage Comparator

Both the inputs and the outputs of the LM111, LM211 or the LM311 can be isolated from system ground, and the output can drive loads referred to ground, the positive supply or the negative supply. Offset balancing and strobe capability are provided and outputs can be wire ORed.
  • Operates from single 5V supply
  • Input current: 150 nA max. over temperature
  • Offset current: 20 nA max. over temperature
  • Differential input voltage range: ±30V
  • Power consumption: 135 mW at ±15V
Related Resources -

Voltage Comparator Information And Circuits

This page provides basic information about voltage comparator integrated circuits and is to act as reference material for other circuits. The circuits shown are based on the LM339 Quad Voltage Comparator chip or the LM393 Dual Voltage Comparator chip. These devices are functionally the same. The LM311 Voltage Comparator can be used for these applications as well but it also has a number of unique features.

Comparators and Schmitt Triggers

An LM311 in a comparator circuit is shown at the right, with the pin numbers for the connections. The open-collector output is at pin 7, and the ground for this transistor is at pin 1. It is shown pulled up to the logic voltage of +5 with a 1k resistor, which is typical. The output of the LM311 can sink 8 mA. A comparator's output is essentially binary, YES or NO.