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Applied Electronic Circuit #5

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Presentation on theme: "Applied Electronic Circuit #5"โ€” Presentation transcript:

1 Applied Electronic Circuit #5
Howland Current Pump, Difference Amp, Resister Mismatch ์ œ์ถœ์ผ : ์ƒ์ฒด์˜๊ณตํ•™๊ณผ ๋ฐ• ์ค€ ํ™˜

2 1. Howland Current Pump 0๐‘‰ * ๐‘ฃ ๐‘‚ =โˆ’ ๐‘ฃ ๐ฟ ์ด๋ฏ€๋กœ ๐‘ฃ ๐‘‚๐ป โ‰ค ๐‘ฃ ๐‘‚ โ‰ค ๐‘ฃ ๐‘‚๐ฟ
๐‘‰ ๐‘– * ๐‘ฃ ๐‘‚ =โˆ’ ๐‘ฃ ๐ฟ ์ด๋ฏ€๋กœ ๐‘ฃ ๐‘‚๐ป โ‰ค ๐‘ฃ ๐‘‚ โ‰ค ๐‘ฃ ๐‘‚๐ฟ โ†’ Voltage Compliance๊ฐ€ ํฌ๋‹ค. ๐‘– ๐‘œ + ๐‘ฃ ๐ฟ - ๐‘– ๐‘œ = ๐‘‰ ๐‘– ๐‘…1 ๐‘‰ ๐‘œ Grounded Load V-I converter(Single-ended Current source) - Howland Current Pump I๊ฐ€ ๋ชจ๋‘ Load์—๊ฒŒ โ†’ ์ €ํ•ญ โˆž ๐‘๐ผ๐ถ + ๐‘‰ ๐‘– ๐‘…1 ๐‘ฃ ๐ฟ โˆ’ ๐‘…3 ๐‘…4 ๐‘…2 - ์‹ ํ˜ธ์› NIC LOAD

3 1. Howland Current Pump * Balanced Current Source
โˆ— ๐‘… ๐‘‚ = ๐‘… 1 ๐ผ๐ผ ๐‘…3 ๐‘…4 ๐‘…2 = ๐‘…2 ๐‘…2 ๐‘…1 + ๐‘…4 ๐‘…3 ๐‘…2 ๐‘…1 = ๐‘…4 ๐‘…3 ์ด๋ฉด, ๐‘…๐‘œ๋Š” ๋ฌดํ•œ๋Œ€์ด๋‹ค. โˆ—๐‘‰๐‘œ๐‘™๐‘ก๐‘Ž๐‘”๐‘’ ๐ถ๐‘œ๐‘š๐‘๐‘™๐‘–๐‘Ž๐‘›๐‘๐‘’ ๐‘‰ ๐ฟ = ๐‘‰ ๐‘ƒ = ๐‘‰ ๐‘ = ๐‘…3 ๐‘…3+๐‘…4 ๐‘‰ ๐‘œ = ๐‘…1 ๐‘…1+๐‘…2 ๐‘‰ ๐‘œ โˆด ๐‘…1 ๐‘…1+๐‘…2 ๐‘‰ ๐‘‚๐ฟ โ‰ค ๐‘‰ ๐ฟ โ‰ค ๐‘…1 ๐‘…1+๐‘…2 ๐‘‰ ๐‘‚๐ป - R2๋ฅผ ์ž‘์€ ๊ฐ’์œผ๋กœ ์‚ฌ์šฉ ๐‘–

4 1. Howland Current Pump * ์ •์ „๋ฅ˜ ์ „๊ธฐ ์ž๊ทน๊ธฐ

5 1. Howland Current Pump Resister Matching(์ €ํ•ญ์˜ ์˜ค์ฐจ๋ฅผ ์ƒ๊ฐํ•ด์„œ ๋‹ค์‹œ ๋ถ„์„)
- ๐‘…2 ๐‘…1 1โˆ’๐œ€ = ๐‘…4 ๐‘…3 โ†’ ์ตœ๋Œ€์˜ค์ฐจ ๐œ€ ๐‘š๐‘Ž๐‘ฅ =4๐‘, ๐‘… ๐‘œ = ๐‘…1/๐œ€ ๐‘š๐‘Ž๐‘ฅ (๋ฌดํ•œ์ด ์•„๋‹ˆ๋‹ค) ์˜ค์ฐจ๋ฅผ ์ค„์ด๋Š” ๋ฐฉ๋ฒ• ๋ฐฉ๋ฒ• 1. ์ •๋ฐ€์ €ํ•ญ ์‚ฌ์šฉ(0.1% ์ €ํ•ญ) ์˜ˆ) 10k์˜ด, p=0.001, ๐œ€ ๐‘š๐‘Ž๐‘ฅ = 0.004 ๐‘… ๐‘œ = 10๐‘˜ =3.75๐‘€ *์‚ฌ์šฉํ•œ ์ €ํ•ญ์˜ ์˜ค์ฐจ ํ™•์ธ์ด ๋ฐ˜๋“œ์‹œ ํ•„์š” ๋ฐฉ๋ฒ• 2. ๊ฐ€๋ณ€์ €ํ•ญ ์‚ฌ์šฉ 15๐‘˜ฮฉ

6 ์‹คํ—˜์ ์œผ๋กœ ์ €ํ•ญ์„ Matching ์‹œ์ผœ์ฃผ์–ด์•ผ ํ•œ๋‹ค.
1. Howland Current Pump ์–ด๋–ป๊ฒŒ ์ €ํ•ญ ์กฐ์ ˆ์ด ์ž˜ ๋˜์—ˆ๋Š”์ง€ ์•Œ ์ˆ˜ ์žˆ์„๊นŒ? Mismatch - Ro : ์œ ํ•œ, A โ‰  0 Match - Ro : ๋ฌดํ•œ, A = 0 ์กฐ์ ˆ A ์‹คํ—˜์ ์œผ๋กœ ์ €ํ•ญ์„ Matching ์‹œ์ผœ์ฃผ์–ด์•ผ ํ•œ๋‹ค. - ๋Œ€๋Ÿ‰์ƒ์‚ฐ์— ๋ถˆ๋ฆฌ(โˆต์ƒ์‚ฐ์„ฑโ†“)

7 2. Difference Amp โˆ— ๐‘‰ ๐ท๐‘€ = ๐‘‰ 2 โˆ’ ๐‘‰ 1 (Differential Mode Signal)
โˆ— ๐‘‰ ๐ถ๐‘€ = 1 2 ( ๐‘‰ 2 + ๐‘‰ 1 )(Common Mode Signal) - ๐‘‰ 1 = ๐‘‰ ๐ถ๐‘€ โˆ’ ๐‘‰ ๐ท๐‘€ - ๐‘‰ 2 = ๐‘‰ ๐ถ๐‘€ ๐‘‰ ๐ท๐‘€ ๐‘‰ 1 ๐‘‰ 2 ๐‘‰ ๐‘œ = ๐‘…2 ๐‘…1 (๐‘‰ 2 โˆ’ ๐‘‰ 1 ) ๐‘‰ 1 ๐‘‰ ๐ถ๐‘€ 1 2 ๐‘‰ ๐ท๐‘€ ๋“ฑ๊ฐ€ํšŒ๋กœ 1 2 ๐‘‰ ๐ท๐‘€ ๐‘‰ ๐‘œ ๐‘‰ 2

8 3. Resister Mismatch โ€“ use superposition
๐‘‰ 1 ๐‘… 2 (1โˆ’๐œ€) ๐‘‰ ๐‘œ =โˆ’ ๐‘…2 ๐‘…1 ( 1โˆ’๐œ€)๐‘‰ ๐‘…2 ๐‘…1 1โˆ’๐œ€ ๐‘…2 ๐‘…1+๐‘…2 ๐‘‰ 2 = ๐‘…2 ๐‘…1 1+ ๐‘…1+2๐‘…2 ๐‘…1+๐‘…2 ๐œ€ 2 ๐‘‰ ๐ท๐‘€ + ๐‘…2 ๐‘…1+๐‘…2 ๐‘‰ ๐ถ๐‘€ * ๐ด ๐ท๐‘€ : Differential Mode Gain * ๐ด ๐ถ๐‘€ : Common Mode Gain ๐‘‰ ๐ถ๐‘€ 1 2 ๐‘‰ ๐ท๐‘€ 1 2 ๐‘‰ ๐ท๐‘€ ๐‘‰ ๐‘œ ๐‘‰ 2 ๐‘‰ ๐‘œ (๐‘ก) ๐œ€=0 ๐‘‰ ๐‘œ (๐‘ก) ๐œ€โ‰ 0 ๐‘ก ๐‘ก DC ์ „์••์ด ์ƒ๊น€

9 3. Resister Mismatch โ€“ use superposition
CMRR(Common Mode Rejection Ratio) 20 ๐‘™๐‘œ๐‘” ๐ด ๐ท๐‘€ ๐ด ๐ถ๐‘€ โ‰ˆ 20๐‘™๐‘œ๐‘” ๐‘…2 ๐‘…1 ๐œ€ , lim ๐‘›โ†’0 ๐ถ๐‘€๐‘…๐‘…=โˆž Resister tuning ( ์ •๋ฐ€์ €ํ•ญ ์‚ฌ์šฉ, ๊ฐ€๋ณ€์ €ํ•ญ ์‚ฌ์šฉ) ๐‘‰ 1 ๐‘‰ ๐ถ๐‘€ ๐‘‰ ๐ถ๐‘€ ์„ ๋™์ผํ•˜๊ฒŒ ์ธ๊ฐ€ํ•˜์˜€์„ ๋•Œ ์ถœ๋ ฅ์ „์••์ด 0์œผ๋กœ ๋‚˜์™€์•ผ ํ•œ๋‹ค. ๐‘‰ 2

10 3. Resister Mismatch โ€“ use superposition
๐‘‰ ๐ถ๐‘€ =5๐‘‰์ผ ๋•Œ ๐‘‰ ๐‘œ (๐‘ก) ๐ด ๐ถ๐‘€ โˆ— = ๐‘‰ ๐‘œ โˆ— 5 :์‹คํ—˜์ ์œผ๋กœ ํ™•์ธํ•œ ๐บ๐‘Ž๐‘–๐‘› โ†’๐ถ๐‘€๐‘…๐‘…=20 ๐‘™๐‘œ๐‘” ๐ด ๐ท๐‘€ ๐ด ๐ถ๐‘€ โˆ— ๐‘‰ ๐‘œ โˆ— ๐ด ๐ถ๐‘€ = ๐‘‰ ๐‘œ โˆ— ๐‘‰ ๐ถ๐‘€ 1% ์ €ํ•ญ ์‚ฌ์šฉ ๐‘‰ ๐‘œ (๐‘ก) ๐‘‰ ๐‘œ โˆ— cos 2๐œ‹โˆ—60๐‘ก ๐‘‰ 1 ๐‘‰ 2 ๐‘‰ ๐ถ๐‘€ ๐‘ก = ๐‘‰ ๐ถ๐‘€ cos 2๐œ‹โˆ—60๐‘ก [๐‘‰]

11 ๊ฐ์‚ฌํ•ฉ๋‹ˆ๋‹ค.


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