ST7PMC2N6B6(2004) View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

ST7PMC2N6B6
(Rev.:2004)

8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC, BRUSHLESS MOTOR CONTROL, FIVE TIMERS, SPI, LINSCI™

STMicroelectronics 

ST7MC1/ST7MC2

MOTOR CONTROL CHARACTERISTICS (Cont’d)

11.12.3 Input Stage (Current Feedback Comparator + Sampling)

Symbol

VIN

Voffset

Ioffset

tpropag

tstartup

tsampling

Parameter

Conditions

Min

Typ

Max Unit

Comparator input voltage range

Comparator offset error

VSSA - 0.1

VDD + 0.1 V

5

40 1)

mV

Input offset current

0

1

µA

Comparator propagation

delay 1)

35

100

ns

Startup filter duration 2)

Time waited before sampling

when comparator is turned

ON, i.e. CKE=1 or DAC=1

(with fPERIPH = 4MHz)

Time needed to turn OFF the

MCOs when comparator out-

put rises (CFF=0)

3

µs

4 / f MTC (see Figure 149)

Digital sampling delay 3)

Time between a comparator

toggle (current loop event)

and bit CL becoming set

(CFF=0)

Time needed to turn OFF the

MCOs when comparator out-

put rises (CFF=x)

2 / f MTC (see Figure 149)

(1+x) * (4 / fPERIPH) + (3 / fmtc)

(see Figure 150)

Time between a comparator

toggle (current loop event)

and bit CL becoming set

(CFF=x)

(1+x) * (4 / fPERIPH) + (1 / fmtc)

(see Figure 150)

Note :

1. The comparator accuracy is dependent of the environment. The offset value is given for a comparison done with all

digital I/Os stable. Negative injection current on the I/Os close to the inputs may reduce the accuracy. In particular care

must be taken to avoid switching on I/Os close to the inputs when the comparator is in use. This phenomenon is even

more critical when a big external serial resistor is added on the inputs.

2. This filter is implemented to wait for comparator stabilization and avoid any wrong information during startup.

3.This delay represents the number of clock cycles needed to generate an event as soon as the comparator ouput chang-

es.

Example : When CFF=0 (detection is based on a single detection), MCO outputs are turned OFF at the 4th clock cycle

after comparator commutation, i.e. there is a variation of (1/fmtc) or (4 / fPERIPH) depending on the case.

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